diff -u b/guestbook.install b/guestbook.install
--- b/guestbook.install
+++ b/guestbook.install
@@ -44,6 +44,7 @@
   db_update('role_permission')
     ->fields(array('permission' => 'moderate all guestbooks'))
     ->condition('permission', 'administer all guestbooks')
+    ->condition('module', 'guestbook')
     ->execute();
 }