diff --git a/pandora_console/ChangeLog b/pandora_console/ChangeLog
index a5bfdd4d0a..2f9fb0794a 100644
--- a/pandora_console/ChangeLog
+++ b/pandora_console/ChangeLog
@@ -1,3 +1,9 @@
+2010-09-08  Ramon Novoa  <rnovoa@artica.es>
+
+	* include/functions_reporting.php,
+	  operation/reporting/reporting_xml.php: Improved error detection in
+	  reports.
+
 2010-09-07  Sancho Lerena <slerena@artica.es>
 
 	* pandoradb_data.sql: Fixed typo in data SQL.
diff --git a/pandora_console/include/functions_reporting.php b/pandora_console/include/functions_reporting.php
index bf51087288..820f632266 100644
--- a/pandora_console/include/functions_reporting.php
+++ b/pandora_console/include/functions_reporting.php
@@ -74,7 +74,7 @@ function get_agentmodule_data_average ($id_agent_module, $period, $date = 0) {
 		if ($next_data !== false) {
 			$next_data['utimestamp'] = $date;
 			array_push ($interval_data, $next_data);
-		} else {
+		} else if (count ($interval_data) > 0) {
 			// Propagate the last known data to the end of the interval
 			$next_data = array_pop ($interval_data);
 			array_push ($interval_data, $next_data);
@@ -86,7 +86,7 @@ function get_agentmodule_data_average ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < $min_necessary) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -168,7 +168,7 @@ function get_agentmodule_data_max ($id_agent_module, $period, $date = 0) {
 		if ($next_data !== false) {
 			$next_data['utimestamp'] = $date;
 			array_push ($interval_data, $next_data);
-		} else {
+		} else if (count ($interval_data) > 0) {
 			// Propagate the last known data to the end of the interval
 			$next_data = array_pop ($interval_data);
 			array_push ($interval_data, $next_data);
@@ -240,7 +240,7 @@ function get_agentmodule_data_min ($id_agent_module, $period, $date = 0) {
 		if ($next_data !== false) {
 			$next_data['utimestamp'] = $date;
 			array_push ($interval_data, $next_data);
-		} else {
+		} else if (count ($interval_data) > 0) {
 			// Propagate the last known data to the end of the interval
 			$next_data = array_pop ($interval_data);
 			array_push ($interval_data, $next_data);
@@ -250,7 +250,7 @@ function get_agentmodule_data_min ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < 1) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -320,7 +320,7 @@ function get_agentmodule_data_sum ($id_agent_module, $period, $date = 0) {
 		if ($next_data !== false) {
 			$next_data['utimestamp'] = $date;
 			array_push ($interval_data, $next_data);
-		} else {
+		} else if (count ($interval_data) > 0) {
 			// Propagate the last known data to the end of the interval
 			$next_data = array_pop ($interval_data);
 			array_push ($interval_data, $next_data);
@@ -332,7 +332,7 @@ function get_agentmodule_data_sum ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < $min_necessary) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -445,7 +445,7 @@ function get_agentmodule_sla ($id_agent_module, $period = 0, $min_value = 1, $ma
 	if ($next_data !== false) {
 		$next_data['utimestamp'] = $date;
 		array_push ($interval_data, $next_data);
-	} else {
+	} else if (count ($interval_data) > 0) {
 		// Propagate the last known data to the end of the interval
 		$next_data = array_pop ($interval_data);
 		array_push ($interval_data, $next_data);
@@ -454,7 +454,7 @@ function get_agentmodule_sla ($id_agent_module, $period = 0, $min_value = 1, $ma
 	}
 
 	if (count ($interval_data) < 2) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -1767,10 +1767,17 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			}
 			
 			$data = array ();
-			$monitor_value = format_numeric (get_agentmodule_sla ($content['id_agent_module'], $content['period'], 1, false, $report["datetime"]));
+			$monitor_value = get_agentmodule_sla ($content['id_agent_module'], $content['period'], 1, false, $report["datetime"]);
+			if ($monitor_value === false) {
+				$monitor_value = __('Unknown');
+			} else {
+				$monitor_value = format_numeric ($monitor_value);
+			}
 			$data[0] = '<p style="font: bold '.$sizem.'em Arial, Sans-serif; color: #000000;">';
 			$data[0] .= $monitor_value.' % <img src="images/b_green.png" height="32" width="32" /></p>';
-			$monitor_value = format_numeric (100 - $monitor_value, 2) ;
+			if ($monitor_value !== __('Unknown')) {
+				$monitor_value = format_numeric (100 - $monitor_value, 2) ;
+			}
 			$data[1] = '<p style="font: bold '.$sizem.'em Arial, Sans-serif; color: #ff0000;">';
 			$data[1] .= $monitor_value.' % <img src="images/b_red.png" height="32" width="32" /></p>';
 			array_push ($table->data, $data);
@@ -1795,7 +1802,12 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			
 			$data = array ();
 			$table->colspan[2][0] = 3;
-			$value = format_numeric (get_agentmodule_data_average ($content['id_agent_module'], $content['period'], $report["datetime"]));
+			$value = get_agentmodule_data_average ($content['id_agent_module'], $content['period'], $report["datetime"]);
+			if ($value === false) {
+				$value = __('Unknown');
+			} else {
+				$value = format_numeric ($value);
+			}
 			$data[0] = '<p style="font: bold '.$sizem.'em Arial, Sans-serif; color: #000000;">'.$value.'</p>';
 			array_push ($table->data, $data);
 			
@@ -1843,7 +1855,12 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			
 			$data = array ();
 			$table->colspan[1][0] = 2;
-			$value = format_numeric (get_agentmodule_data_min ($content['id_agent_module'], $content['period'], $report["datetime"]));
+			$value = get_agentmodule_data_min ($content['id_agent_module'], $content['period'], $report["datetime"]);
+			if ($value === false) {
+				$value = __('Unknown');
+			} else {
+				$value = format_numeric ($value);
+			}
 			$data[0] = '<p style="font: bold '.$sizem.'em Arial, Sans-serif; color: #000000;">'.$value.'</p>';
 			array_push ($table->data, $data);
 			
@@ -1867,7 +1884,13 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			
 			$data = array ();
 			$table->colspan[1][0] = 2;
-			$value = format_numeric (get_agentmodule_data_sum ($content['id_agent_module'], $content['period'], $report["datetime"]));
+			$value = get_agentmodule_data_sum ($content['id_agent_module'], $content['period'], $report["datetime"]);
+			if ($value === false) {
+				$value = __('Unknown');
+			} else {
+				$value = format_numeric ($value);
+			}
+
 			$data[0] = '<p style="font: bold '.$sizem.'em Arial, Sans-serif; color: #000000;">'.$value.'</p>';
 			array_push ($table->data, $data);
 			
@@ -2125,7 +2148,11 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			$data = array ();
 			$table->colspan[2][0] = 3;
 			$ttr = get_agentmodule_ttr ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($ttr != 0) $ttr = human_time_description_raw ($ttr);
+			if ($ttr === false) {
+				$ttr = __('Unknown');
+			} else if ($ttr != 0) {
+				$ttr = human_time_description_raw ($ttr);
+			}
 			
 			$data = array ();
 			$table->colspan[2][0] = 3;
@@ -2149,7 +2176,11 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			$data = array ();
 			$table->colspan[2][0] = 3;
 			$tto = get_agentmodule_tto ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($tto != 0) $tto = human_time_description_raw ($tto);
+			if ($tto === false) {
+				$tto = __('Unknown');
+			} else if ($tto != 0) {
+				$tto = human_time_description_raw ($tto);
+			}
 			
 			$data = array ();
 			$table->colspan[2][0] = 3;
@@ -2173,7 +2204,11 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			$data = array ();
 			$table->colspan[2][0] = 3;
 			$mtbf = get_agentmodule_mtbf ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($mtbf != 0) $mtbf = human_time_description_raw ($mtbf);
+			if ($mtbf === false) {
+				$mtbf = __('Unknown');
+			} else if ($mtbf != 0) {
+				$mtbf = human_time_description_raw ($mtbf);
+			}
 			
 			$data = array ();
 			$table->colspan[2][0] = 3;
@@ -2197,7 +2232,11 @@ function render_report_html_item ($content, $table, $report, $mini = false) {
 			$data = array ();
 			$table->colspan[2][0] = 3;
 			$mttr = get_agentmodule_mttr ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($mttr != 0) $mttr = human_time_description_raw ($mttr);
+			if ($mttr === false) {
+				$mttr = __('Unknown');
+			} else if ($mttr != 0) {
+				$mttr = human_time_description_raw ($mttr);
+			}
 			
 			$data = array ();
 			$table->colspan[2][0] = 3;
@@ -2229,7 +2268,7 @@ function get_agentmodule_mtbf ($id_agent_module, $period, $date = 0) {
 				FROM tagente_modulo
 				WHERE id_agente_modulo = ' . (int) $id_agent_module);
 	if ($module === false) {
-		return -1;
+		return false;
 	}
 
 	$critical_min = $module['min_critical'];
@@ -2263,7 +2302,7 @@ function get_agentmodule_mtbf ($id_agent_module, $period, $date = 0) {
 	if ($next_data !== false) {
 		$next_data['utimestamp'] = $date;
 		array_push ($interval_data, $next_data);
-	} else {
+	} else if (count ($interval_data) > 0) {
 		// Propagate the last known data to the end of the interval
 		$next_data = array_pop ($interval_data);
 		array_push ($interval_data, $next_data);
@@ -2272,7 +2311,7 @@ function get_agentmodule_mtbf ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < 2) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -2337,7 +2376,7 @@ function get_agentmodule_mttr ($id_agent_module, $period, $date = 0) {
 				FROM tagente_modulo
 				WHERE id_agente_modulo = ' . (int) $id_agent_module);
 	if ($module === false) {
-		return -1;
+		return false;
 	}
 
 	$critical_min = $module['min_critical'];
@@ -2371,7 +2410,7 @@ function get_agentmodule_mttr ($id_agent_module, $period, $date = 0) {
 	if ($next_data !== false) {
 		$next_data['utimestamp'] = $date;
 		array_push ($interval_data, $next_data);
-	} else {
+	} else if (count ($interval_data) > 0) {
 		// Propagate the last known data to the end of the interval
 		$next_data = array_pop ($interval_data);
 		array_push ($interval_data, $next_data);
@@ -2380,7 +2419,7 @@ function get_agentmodule_mttr ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < 2) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -2444,7 +2483,7 @@ function get_agentmodule_tto ($id_agent_module, $period, $date = 0) {
 				FROM tagente_modulo
 				WHERE id_agente_modulo = ' . (int) $id_agent_module);
 	if ($module === false) {
-		return -1;
+		return false;
 	}
 
 	$critical_min = $module['min_critical'];
@@ -2478,7 +2517,7 @@ function get_agentmodule_tto ($id_agent_module, $period, $date = 0) {
 	if ($next_data !== false) {
 		$next_data['utimestamp'] = $date;
 		array_push ($interval_data, $next_data);
-	} else {
+	} else if (count ($interval_data) > 0) {
 		// Propagate the last known data to the end of the interval
 		$next_data = array_pop ($interval_data);
 		array_push ($interval_data, $next_data);
@@ -2487,7 +2526,7 @@ function get_agentmodule_tto ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < 2) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
@@ -2542,7 +2581,7 @@ function get_agentmodule_ttr ($id_agent_module, $period, $date = 0) {
 				FROM tagente_modulo
 				WHERE id_agente_modulo = ' . (int) $id_agent_module);
 	if ($module === false) {
-		return -1;
+		return false;
 	}
 
 	$critical_min = $module['min_critical'];
@@ -2576,7 +2615,7 @@ function get_agentmodule_ttr ($id_agent_module, $period, $date = 0) {
 	if ($next_data !== false) {
 		$next_data['utimestamp'] = $date;
 		array_push ($interval_data, $next_data);
-	} else {
+	} else if (count ($interval_data) > 0) {
 		// Propagate the last known data to the end of the interval
 		$next_data = array_pop ($interval_data);
 		array_push ($interval_data, $next_data);
@@ -2585,7 +2624,7 @@ function get_agentmodule_ttr ($id_agent_module, $period, $date = 0) {
 	}
 
 	if (count ($interval_data) < 2) {
-		return -1;
+		return false;
 	}
 
 	// Set initial conditions
diff --git a/pandora_console/operation/reporting/reporting_xml.php b/pandora_console/operation/reporting/reporting_xml.php
index 45a6af424a..aeeaa103e0 100644
--- a/pandora_console/operation/reporting/reporting_xml.php
+++ b/pandora_console/operation/reporting/reporting_xml.php
@@ -231,29 +231,57 @@ foreach ($contents as $content) {
 		case 6:
 		case 'monitor_report':
 			$data["title"] = __('Monitor report');
-			$monitor_value = format_numeric (get_agentmodule_sla ($content['id_agent_module'], $content['period'], 1, false, $datetime));
+			$monitor_value = get_agentmodule_sla ($content['id_agent_module'], $content['period'], 1, false, $datetime);
+			if ($monitor_value === false) {
+				$monitor_value = __('Unknown');
+			} else {
+				$monitor_value = format_numeric ($monitor_value);
+			}
 			$data["objdata"]["good"] = $monitor_value;
-			$data["objdata"]["bad"] = format_numeric (100 - $monitor_value, 2);
+			if ($monitor_value !== __('Unknown')) {
+				$monitor_value = format_numeric (100 - $monitor_value);
+			}
+			$data["objdata"]["bad"] = $monitor_value;
 			break;
 		case 7:
 		case 'avg_value':
 			$data["title"] = __('Avg. Value');
-			$data["objdata"] = format_numeric (get_agentmodule_data_average ($content['id_agent_module'], $content['period'], $datetime));
+			$data["objdata"] = get_agentmodule_data_average ($content['id_agent_module'], $content['period'], $datetime);
+			if ($data["objdata"] === false) {
+				$data["objdata"] = __('Unknown');
+			} else {
+				$data["objdata"] = format_numeric ($data["objdata"]);
+			}
 			break;
 		case 8:
 		case 'max_value':
 			$data["title"] = __('Max. Value');
-			$data["objdata"] = format_numeric (get_agentmodule_data_max ($content['id_agent_module'], $content['period'], $datetime));
+			$data["objdata"] = get_agentmodule_data_max ($content['id_agent_module'], $content['period'], $datetime);
+			if ($data["objdata"] === false) {
+				$data["objdata"] = __('Unknown');
+			} else {
+				$data["objdata"] = format_numeric ($data["objdata"]);
+			}
 			break;
 		case 9:
 		case 'min_value':
 			$data["title"] = __('Min. Value');
-			$data["objdata"] = format_numeric (get_agentmodule_data_min ($content['id_agent_module'], $content['period'], $datetime));
+			$data["objdata"] = get_agentmodule_data_min ($content['id_agent_module'], $content['period'], $datetime);
+			if ($data["objdata"] === false) {
+				$data["objdata"] = __('Unknown');
+			} else {
+				$data["objdata"] = format_numeric ($data["objdata"]);
+			}
 			break;
 		case 10:
 		case 'sumatory':
 			$data["title"] = __('Sumatory');
-			$data["objdata"] = format_numeric (get_agentmodule_data_sum ($content['id_agent_module'], $content['period'], $datetime));
+			$data["objdata"] = get_agentmodule_data_sum ($content['id_agent_module'], $content['period'], $datetime);
+			if ($data["objdata"] === false) {
+				$data["objdata"] = __('Unknown');
+			} else {
+				$data["objdata"] = format_numeric ($data["objdata"]);
+			}
 			break;
 //		case 11:
 //		case 'general_group_report':
@@ -506,31 +534,47 @@ foreach ($contents as $content) {
 			break;
 		case 'TTRT':
 			$ttr = get_agentmodule_ttr ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($ttr != 0) $ttr = human_time_description_raw ($ttr);
-			
+			if ($ttr === false) {
+				$ttr = __('Unknown');
+			} else if ($ttr != 0) {
+				$ttr = human_time_description_raw ($ttr);
+			}
+
 			$data["title"] = __('TTRT');
-			$data["objdata"] = format_numeric($ttr);
+			$data["objdata"] = $ttr;
 			break;
 		case 'TTO':
 			$tto = get_agentmodule_tto ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($tto != 0) $tto = human_time_description_raw ($tto);
+			if ($tto === false) {
+				$tto = __('Unknown');
+			} else if ($tto != 0) {
+				$tto = human_time_description_raw ($tto);
+			}
 				
 			$data["title"] =  __('TTO');
-			$data["objdata"] = format_numeric($tto);
+			$data["objdata"] = $tto;
 			break;
 		case 'MTBF':
 			$mtbf = get_agentmodule_mtbf ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($mtbf != 0) $mtbf = human_time_description_raw ($mtbf);
+			if ($mtbf === false) {
+				$mtbf = __('Unknown');
+			} else if ($mtbf != 0) {
+				$mtbf = human_time_description_raw ($mtbf);
+			}
 				
 			$data["title"] = __('MTBF');
-			$data["objdata"] = format_numeric($mtbf);
+			$data["objdata"] = $mtbf;
 			break;
 		case 'MTTR':
 			$mttr = get_agentmodule_mttr ($content['id_agent_module'], $content['period'], $report["datetime"]);
-			if ($mttr != 0) $mttr = human_time_description_raw ($mttr);
+			if ($mttr === false) {
+				$mttr = __('Unknown');
+			} else if ($mttr != 0) {
+				$mttr = human_time_description_raw ($mttr);
+			}
 				
 			$data["title"] = __('MTTR');
-			$data["objdata"] = format_numeric($mttr);
+			$data["objdata"] = $mttr;
 			break;
 	}
 	xml_array ($data);