diff -rup drupal-7.x-dev/modules/user/user.admin.inc drupal-7.x-dev_new/modules/user/user.admin.inc
--- drupal-7.x-dev/modules/user/user.admin.inc	2010-10-20 12:31:07.000000000 +1100
+++ modules/user/user.admin.inc	2010-10-28 10:14:19.693976004 +1100
@@ -7,10 +7,10 @@
  */
 
 function user_admin($callback_arg = '') {
-  $op = isset($_POST['op']) ? $_POST['op'] : $callback_arg;
+  $op = isset($_POST['form_id']) ? $_POST['form_id'] : $callback_arg;
 
   switch ($op) {
-    case t('Create new account'):
+    case 'user_register_form':
     case 'create':
       $build['user_register'] = drupal_get_form('user_register_form');
       break;