Index: smartqueue.module
===================================================================
--- smartqueue.module	(revision 15)
+++ smartqueue.module	(working copy)
@@ -209,6 +209,10 @@
         // If a term was deleted, we need to delete any subqueues containing it.
         case 'delete':
           $tid = $array['tid'];
+          if(!$tid) {
+            return $tid;
+          }
+          
           // Find subqueues that contain this term.
           $result = db_query(
             "SELECT sq.sqid FROM {nodequeue_subqueue} sq