diff --git a/rietveld.py b/rietveld.py
index aa5897e62..7e476fb6d 100644
--- a/rietveld.py
+++ b/rietveld.py
@@ -365,7 +365,8 @@ class Rietveld(object):
         m = re.search(r'(50\d) Server Error', msg)
         if m:
           # Fake an HTTPError exception. Cheezy. :(
-          raise urllib2.HTTPError(request_path, m.group(1), msg, None, None)
+          raise urllib2.HTTPError(
+              request_path, int(m.group(1)), msg, None, None)
         old_error_exit(msg)
       upload.ErrorExit = trap_http_500