diff --git a/library/Icinga/Application/Config.php b/library/Icinga/Application/Config.php
index e81e8062f..f794d46a0 100644
--- a/library/Icinga/Application/Config.php
+++ b/library/Icinga/Application/Config.php
@@ -61,7 +61,10 @@ class Config extends Zend_Config
             $this->configFile = $filepath;
             $this->merge(new Zend_Config_Ini($filepath));
         } else {
-            throw new NotReadableError('Cannot read config file "' . $filename . '". Permission denied');
+            throw new NotReadableError(
+                'Cannot read config file "%s". Permission denied',
+                $filename
+            );
         }
     }
 
diff --git a/library/Icinga/Application/Modules/Manager.php b/library/Icinga/Application/Modules/Manager.php
index 366f77c30..4154d2c20 100644
--- a/library/Icinga/Application/Modules/Manager.php
+++ b/library/Icinga/Application/Modules/Manager.php
@@ -110,12 +110,14 @@ class Manager
         }
         if (!is_dir($this->enableDir)) {
             throw new NotReadableError(
-                'Cannot read enabled modules. Module directory "' . $this->enableDir . '" is not a directory'
+                'Cannot read enabled modules. Module directory "%s" is not a directory',
+                $this->enableDir
             );
         }
         if (!is_readable($this->enableDir)) {
             throw new NotReadableError(
-                'Cannot read enabled modules. Module directory "' . $this->enableDir . '" is not readable'
+                'Cannot read enabled modules. Module directory "%s" is not readable',
+                $this->enableDir
             );
         }
         if (($dh = opendir($canonical)) !== false) {
diff --git a/library/Icinga/Exception/NotReadableError.php b/library/Icinga/Exception/NotReadableError.php
index 6bc4fc55f..41a7ec8fd 100644
--- a/library/Icinga/Exception/NotReadableError.php
+++ b/library/Icinga/Exception/NotReadableError.php
@@ -4,8 +4,6 @@
 
 namespace Icinga\Exception;
 
-use RuntimeException;
-
-class NotReadableError extends RuntimeException
+class NotReadableError extends IcingaException
 {
 }
diff --git a/library/Icinga/User/Preferences/Store/DbStore.php b/library/Icinga/User/Preferences/Store/DbStore.php
index 728637a35..c0818f303 100644
--- a/library/Icinga/User/Preferences/Store/DbStore.php
+++ b/library/Icinga/User/Preferences/Store/DbStore.php
@@ -78,7 +78,9 @@ class DbStore extends PreferencesStore
                 ->fetchAll();
         } catch (Exception $e) {
             throw new NotReadableError(
-                'Cannot fetch preferences for user ' . $this->getUser()->getUsername() . ' from database', 0, $e
+                'Cannot fetch preferences for user %s from database',
+                $this->getUser()->getUsername(),
+                $e
             );
         }
 
diff --git a/library/Icinga/User/Preferences/Store/IniStore.php b/library/Icinga/User/Preferences/Store/IniStore.php
index eb1c4cbfb..93b31b82b 100644
--- a/library/Icinga/User/Preferences/Store/IniStore.php
+++ b/library/Icinga/User/Preferences/Store/IniStore.php
@@ -62,8 +62,9 @@ class IniStore extends PreferencesStore
         if (file_exists($this->preferencesFile)) {
             if (!is_readable($this->preferencesFile)) {
                 throw new NotReadableError(
-                    'Preferences INI file ' . $this->preferencesFile . ' for user '
-                    . $this->getUser()->getUsername() . ' is not readable'
+                    'Preferences INI file %s for user %s is not readable',
+                    $this->preferencesFile,
+                    $this->getUser()->getUsername()
                 );
             } else {
                 $this->preferences = parse_ini_file($this->preferencesFile);