Index: includes/form.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/form.inc,v
retrieving revision 1.265.2.8
diff -u -p -r1.265.2.8 form.inc
--- includes/form.inc	12 Aug 2008 10:23:48 -0000	1.265.2.8
+++ includes/form.inc	13 Aug 2008 04:44:52 -0000
@@ -1734,7 +1734,7 @@ function expand_radios($element) {
           '#attributes' => $element['#attributes'],
           '#parents' => $element['#parents'],
           '#id' => form_clean_id('edit-'. implode('-', $parents_for_id)),
-          '#ahah' => $element['#ahah'],
+          '#ahah' => isset($element['#ahah']) ? $element['#ahah'] : NULL,
         );
       }
     }