Comment 1 for bug 645213

I hope this helps:

Traceback (most recent call last):
  File "/usr/share/kupfer/kupfer/ui/browser.py", line 1314, in _activate
    self.data_controller.activate()
  File "/usr/share/kupfer/kupfer/core/data.py", line 752, in activate
    res, ret = ctx.run(leaf, action, sobject)
  File "/usr/share/kupfer/kupfer/commandexec.py", line 249, in run
    ret = activate_action(obj, action, iobj)
  File "/usr/share/kupfer/kupfer/commandexec.py", line 74, in activate_action
    return _activate_action_single(obj, action, iobj)
  File "/usr/share/kupfer/kupfer/commandexec.py", line 82, in _activate_action_single
    ret = action.activate(obj)
  File "/usr/share/kupfer/kupfer/plugin/twitter/__init__.py", line 199, in activate
    api.PostUpdate(trunc_message(leaf.object))
  File "/usr/lib/pymodules/python2.6/twitter.py", line 1492, in PostUpdate
    json = self._FetchUrl(url, post_data=data)
  File "/usr/lib/pymodules/python2.6/twitter.py", line 2016, in _FetchUrl
    url_data = opener.open(url, encoded_post_data).read()
  File "/usr/lib/python2.6/urllib2.py", line 397, in open
    response = meth(req, response)
  File "/usr/lib/python2.6/urllib2.py", line 510, in http_response
    'http', request, response, code, msg, hdrs)
  File "/usr/lib/python2.6/urllib2.py", line 435, in error
    return self._call_chain(*args)
  File "/usr/lib/python2.6/urllib2.py", line 369, in _call_chain
    result = func(*args)
  File "/usr/lib/python2.6/urllib2.py", line 518, in http_error_default
    raise HTTPError(req.get_full_url(), code, msg, hdrs, fp)
urllib2.HTTPError: HTTP Error 401: Unauthorized