diff --git a/classes/Mail.php b/classes/Mail.php
index d64118514..783983964 100644
--- a/classes/Mail.php
+++ b/classes/Mail.php
@@ -217,7 +217,7 @@ class MailCore
 			else if ($module_name && file_exists($theme_path.'mails/'.$iso.'/lang.php'))
 				include_once($theme_path.'mails/'.$iso.'/lang.php');
 			else
-				include_once(_MAIL_DIR_.$iso.'/lang.php');
+				include_once(_PS_MAIL_DIR_.$iso.'/lang.php');
 
 			/* Create mail and attach differents parts */
 			$message = new Swift_Message('['.Configuration::get('PS_SHOP_NAME').'] '.$subject);