diff --git a/gulliver/system/class.rbac.php b/gulliver/system/class.rbac.php
index 93687574b..13be2742d 100644
--- a/gulliver/system/class.rbac.php
+++ b/gulliver/system/class.rbac.php
@@ -1771,8 +1771,8 @@ class RBAC
      * Returns true in case the parameter corresponds to the invited user, 
      * otherwise it returns false.
      * 
-     * @param boolean $usrUid
-     * @return void
+     * @param string $usrUid
+     * @return boolean
      */
     public static function isGuestUserUid($usrUid)
     {