Index: rules/rules.module
===================================================================
--- rules/rules.module	(revision 1592)
+++ rules/rules.module	(working copy)
@@ -822,7 +822,7 @@
  */
 function rules_item_delete($item_type, $name) {
   if ($info = rules_get_items($item_type)) {
-    rules_item_type_invoke($item_type, 'delete', $name);
+    rules_item_type_invoke($item_type, 'delete', (array)$name);
     db_query("DELETE FROM {". $info['db_table'] ."} WHERE name = '%s'", $name);
   }
 }