diff --git a/phpBB/download/file.php b/phpBB/download/file.php
index e21aec5ee7..d33e1723ca 100644
--- a/phpBB/download/file.php
+++ b/phpBB/download/file.php
@@ -402,7 +402,7 @@ else
 	if ($files_added < 1)
 	{
 		// None of the attachments had a valid a extension
-		$disallowed = implode(', ', $disallowed);
+		$disallowed = implode($user->lang['COMMA_SEPARATOR'], $disallowed);
 		send_status_line(404, 'Forbidden');
 		trigger_error($user->lang('EXTENSION_DISABLED_AFTER_POSTING', $disallowed));
 	}