Index: includes/menu.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/menu.inc,v
retrieving revision 1.255.2.9
diff -u -p -r1.255.2.9 menu.inc
--- includes/menu.inc	27 Feb 2008 12:12:01 -0000	1.255.2.9
+++ includes/menu.inc	5 Mar 2008 21:17:59 -0000
@@ -1486,9 +1486,9 @@ function menu_set_active_trail($new_trai
       }
       else {
         // Move to the child link if it's in the active trail.
-        if ($curr['below'] && $curr['link']['in_active_trail']) {
+        if ($curr['link']['in_active_trail']) {
           $trail[] = $curr['link'];
-          $tree = $curr['below'];
+          $tree = $curr['below'] ?  $curr['below'] : array();
         }
         list($key, $curr) = each($tree);
       }