diff -Naur protect_critical_users/protect_critical_users.module protect_critical_users.new/protect_critical_users.module
--- protect_critical_users/protect_critical_users.module	2008-11-19 22:51:00.000000000 +0100
+++ protect_critical_users.new/protect_critical_users.module	2011-09-27 13:54:48.427768481 +0200
@@ -20,8 +20,12 @@
       drupal_goto($uid == 0 ? '<front>' : 'user/'. $uid .'/edit');
     }
     else if ($uid == $user->uid) {
-      drupal_set_message(t('Oops! You cannot delete your own account!'), 'error');
-      drupal_goto('user/'. $uid .'/edit');
+      // Own account deletion managed by user_delete module, if present
+      // @see http://drupal.org/node/507890
+      if (!module_exists('user_delete')) {
+        drupal_set_message(t('Oops! You cannot delete your own account!'), 'error');
+        drupal_goto('user/'. $uid .'/edit');
+      }
     }
   }
 
@@ -48,7 +52,7 @@
 
   // Remove delete button from user 1 edit form.
   if ($form_id == 'user_profile_form' && isset($form['delete']) && isset($form['_account']['#value']->uid)) {
-    if ($form['_account']['#value']->uid == 1 || $form['_account']['#value']->uid == $user->uid) {
+    if ( $form['_account']['#value']->uid == 1 || ($form['_account']['#value']->uid == $user->uid && !module_exists('user_delete')) ) {
       unset($form['delete']);
     }
   }