diff --git a/addons/userrights/userrightsnull.class.inc.php b/addons/userrights/userrightsnull.class.inc.php
index da3f35548..cb8d351d2 100644
--- a/addons/userrights/userrightsnull.class.inc.php
+++ b/addons/userrights/userrightsnull.class.inc.php
@@ -74,7 +74,7 @@ class UserRightsNull extends UserRightsAddOnAPI
 		return UR_ALLOWED_YES;
 	}
 
-	public static function FlushPrivileges()
+	public function FlushPrivileges()
 	{
 	}
 }