diff -rup admin/includes/jquery.drilldown.js admin_new/includes/jquery.drilldown.js
--- admin/includes/jquery.drilldown.js	2010-08-07 01:31:44.000000000 +1000
+++ includes/jquery.drilldown.js	2011-01-25 16:15:39.731475000 +1100
@@ -80,7 +80,8 @@
         if (breadcrumb.length > 0) {
           var trail = $(settings.trail);
           trail.empty();
-          for (var key in breadcrumb) {
+          var numberOfCrumbs = breadcrumb.length;
+          for (var key = 0; key < numberOfCrumbs; key++) {
             if (breadcrumb[key]) {
               // We don't use the $().clone() method here because of an
               // IE & jQuery 1.2 bug.