fixed error when registration was enabled for a user and he looks at /apps, caused by regitering a - not existing - query method in link-registry of registration

phpgwapi/inc/class.egw_link.inc.php

@@ -704,8 +704,8 @@ class egw_link extends solink
 		}
 		else
 		{
-			// Fall back to original method
-			$result = ExecMethod2($method,$pattern,$options);
+			// if there is no object or no method, give a more explaining error message
+			throw new egw_exception_assertion_failed("Object has no method '$reg[query]'!");
 		}
 
 		if (!isset($options['total']))