diff --git a/ad.module b/ad.module
index 6a1baa7..25ad1bd 100644
--- a/ad.module
+++ b/ad.module
@@ -140,7 +140,7 @@ function ad_type_new() {
  *   of query performed to save the ad type.
  */
 function ad_type_save($ad_type) {
-  $op = drupal_write_record('ad_type', $ad_type, empty($ad_type->is_new) ? 'type' : NULL);
+  $op = drupal_write_record('ad_type', $ad_type, empty($ad_type->is_new) ? 'type' : array());
   menu_rebuild();
 
   // If this is a new ad type and the insert did not fail...