Fixed TypeError

src/mra.py

@@ -994,7 +994,7 @@ class MRA(object):
         # full_path = os.path.realpath(os.path.join(root, *args))
         full_path = os.path.join(root, *args)
         if not full_path.startswith(os.path.realpath(root)):
-            raise webapp.Forbidden(message="Path \"%s\" outside root directory." % (args))
+            raise webapp.Forbidden("Path \"%s\" outside root directory." % full_path)
         return full_path
 
     def mk_path(self, path):