Index: /trunk/reviewboard/reviews/views.py
===================================================================
--- /trunk/reviewboard/reviews/views.py	(revision 1980)
+++ /trunk/reviewboard/reviews/views.py	(working copy)
@@ -1,6 +1,8 @@
 import time
 from datetime import datetime
 
+import logging
+
 from django.conf import settings
 from django.contrib.auth.models import User
 from django.contrib.sites.models import Site
@@ -180,8 +182,12 @@
                     bug_url = review_request.repository.bug_tracker
                     for field in info:
                         for i, buginfo in enumerate(info[field]):
-                            info[field][i] = (buginfo[0],
-                                              bug_url % buginfo[0])
+                            try:
+                                full_bug_url = bug_url % buginfo[0]
+                                info[field][i] = (buginfo[0], full_bug_url)
+                            except TypeError:
+                                logging.warning("Invalid bugtracker url format")
+                                info[field][i] = (buginfo[0], None)
 
             elif 'old' in info or 'new' in info:
                 change_type = 'changed'