diff --git a/src/calibre/trac/bzr_commit_plugin.py b/src/calibre/trac/bzr_commit_plugin.py
index 0174a685a9..01e3bc7ab0 100644
--- a/src/calibre/trac/bzr_commit_plugin.py
+++ b/src/calibre/trac/bzr_commit_plugin.py
@@ -86,9 +86,13 @@ class cmd_commit(_cmd_commit):
     def run(self, message=None, file=None, verbose=False, selected_list=None,
             unchanged=False, strict=False, local=False, fixes=None,
             author=None, show_diff=False):
+        nick = config = bug = action = None
         if message:
-            message, bug, url, action, nick, config = \
-                self.expand_message(message, tree_files(selected_list)[0])
+            try:
+                message, bug, url, action, nick, config = \
+                    self.expand_message(message, tree_files(selected_list)[0])
+            except ValueError:
+                pass
         
             if nick and bug and not fixes:
                 fixes = [nick+':'+bug]