If you think this really should work and you can reproduce it, you should consider reporting this problem to the Trac team.

Go to http://trac.edgewall.org/ and create a new ticket where you describe the problem, how to reproduce it. Don't forget to include the Python traceback found below.

TracGuide — The Trac User and Administration Guide
Python Traceback

Traceback (most recent call last):
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/web/main.py", line 335, in dispatch_request
    dispatcher.dispatch(req)
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/web/main.py", line 220, in dispatch
    resp = chosen_handler.process_request(req)
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/versioncontrol/web_ui/browser.py", line 133, in process_request
    self._render_file(req, repos, node, rev)
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/versioncontrol/web_ui/browser.py", line 229, in _render_file
    changeset = repos.get_changeset(node.rev)
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/versioncontrol/cache.py", line 41, in get_changeset
    self.sync()
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/versioncontrol/cache.py", line 95, in sync
    "VALUES (%s,%s,%s,%s)", (str(current_rev),
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/db/util.py", line 47, in execute
    return self.cursor.execute(sql_escape_percent(sql), args)
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/db/sqlite_backend.py", line 44, in execute
    args or [])
  File "/Library/Frameworks/Python.framework/Versions/2.4/lib/python2.4/site-packages/trac/db/sqlite_backend.py", line 36, in _rollback_on_error
    return function(self, *args, **kwargs)
OperationalError: database is locked