python发送带头部的post请求出错是怎么回事？

<code>Traceback (most recent call last):
  File "D:\python\get-email-by-tieba.py", line 49, in <module>
    main()
  File "D:\python\get-email-by-tieba.py", line 6, in main
    getThreadByTid()
  File "D:\python\get-email-by-tieba.py", line 36, in getThreadByTid
    req = urllib2.urlopen(url, post_data, headers)
  File "C:\Python27\lib\urllib2.py", line 126, in urlopen
    return _opener.open(url, data, timeout)
  File "C:\Python27\lib\urllib2.py", line 391, in open
    response = self._open(req, data)
  File "C:\Python27\lib\urllib2.py", line 409, in _open
    '_open', req)
  File "C:\Python27\lib\urllib2.py", line 369, in _call_chain
    result = func(*args)
  File "C:\Python27\lib\urllib2.py", line 1173, in http_open
    return self.do_open(httplib.HTTPConnection, req)
  File "C:\Python27\lib\urllib2.py", line 1142, in do_open
    h.request(req.get_method(), req.get_selector(), req.data, headers)
  File "C:\Python27\lib\httplib.py", line 946, in request
    self._send_request(method, url, body, headers)
  File "C:\Python27\lib\httplib.py", line 987, in _send_request
    self.endheaders(body)
  File "C:\Python27\lib\httplib.py", line 940, in endheaders
    self._send_output(message_body)
  File "C:\Python27\lib\httplib.py", line 803, in _send_output
    self.send(msg)
  File "C:\Python27\lib\httplib.py", line 755, in send
    self.connect()
  File "C:\Python27\lib\httplib.py", line 736, in connect
    self.timeout, self.source_address)
  File "C:\Python27\lib\socket.py", line 557, in create_connection
    sock.settimeout(timeout)
  File "C:\Python27\lib\socket.py", line 222, in meth
    return getattr(self._sock,name)(*args)</code>