Error: Error with navigation contributor AuthRequired

[nardoj]

2010-10-21 09:45:51,014 Trac[api] INFO: Synchronized '' repository in 0.01 seconds
2010-10-21 09:45:51,022 Trac[chrome] ERROR: Error with navigation contributor AuthRequired: RequestDone: 
2010-10-21 09:45:51,362 Trac[main] ERROR: Internal Server Error: 
Traceback (most recent call last):
  File "build/bdist.linux-i686/egg/trac/web/main.py", line 513, in _dispatch_request
    dispatcher.dispatch(req)
  File "build/bdist.linux-i686/egg/trac/web/main.py", line 259, in dispatch
    req.send(output, content_type or 'text/html')
  File "build/bdist.linux-i686/egg/trac/web/api.py", line 409, in send
    self.end_headers()
  File "build/bdist.linux-i686/egg/trac/web/api.py", line 317, in end_headers
    self._write = self._start_response(self._status, self._outheaders)
  File "build/bdist.linux-i686/egg/trac/web/wsgi.py", line 114, in _start_response
    assert not self.headers_set, 'Response already started'
AssertionError: Response already started