diff --git a/system/database/DB_utility.php b/system/database/DB_utility.php
index ecfda52..9eac2ec 100644
--- a/system/database/DB_utility.php
+++ b/system/database/DB_utility.php
@@ -316,7 +316,7 @@
 	 * Database Backup
 	 *
 	 * @param	array	$params
-	 * @return	mixed
+	 * @return	string
 	 */
 	public function backup($params = array())
 	{
@@ -417,7 +417,7 @@
 			return gzencode($this->_backup($prefs));
 		}
 
-		return;
+		return '';
 	}
 
 }