diff --git a/_define.php b/_define.php
index bc24328..d419f00 100644
--- a/_define.php
+++ b/_define.php
@@ -10,7 +10,7 @@
  * @copyright Jean-Christian Denis
  * @copyright GPL-2.0 https://www.gnu.org/licenses/gpl-2.0.html
  */
-if (!defined('DC_RC_PATH')) {
+if (!defined('DC_RC_PATH') || is_null(dcCore::app()->auth)) {
     return null;
 }
 
@@ -22,8 +22,8 @@ $this->registerModule(
     [
         'requires'    => [['core', '2.26']],
         'permissions' => dcCore::app()->auth->makePermissions([
-            dcAuth::PERMISSION_USAGE,
-            dcAuth::PERMISSION_CONTENT_ADMIN,
+            dcCore::app()->auth::PERMISSION_USAGE,
+            dcCore::app()->auth::PERMISSION_CONTENT_ADMIN,
         ]),
         'type'       => 'plugin',
         'support'    => 'http://forum.dotclear.org/viewforum.php?id=16',