diff --git a/core/oql/check_oql.php b/core/oql/check_oql.php
index 679f9bfa07..08960aec0d 100644
--- a/core/oql/check_oql.php
+++ b/core/oql/check_oql.php
@@ -20,9 +20,12 @@
  *     echo "Ok, '$sOQL' is a valid query";
  * }
  */
-class CoreException extends Exception
+if (!class_exists('CoreException', false))
 {
-
+	class CoreException extends Exception
+	{
+	
+	}
 }
 
 require_once(__DIR__.'/expression.class.inc.php');