BUG 6692 Adjustment to verify if the folder exists

gulliver/system/class.rbac.php

@@ -1031,6 +1031,8 @@ class RBAC
 
 private function getAllFiles($directory, $recursive = true ) {
     $result = array();
+    if (is_dir($directory))
+    {
       $handle =  opendir($directory);
       while ($datei = readdir($handle))
       {
@@ -1047,6 +1049,7 @@ private function getAllFiles($directory, $recursive = true ) {
           }
       }
       closedir($handle);
+    }
     return $result;
 }