Here's the most recent traceback:

  File "/home/delimy/temp/Python-3.0a4/Lib/wsgiref/handlers.py", line
116, in finish_response
    self.write(data)
  File "/home/delimy/temp/Python-3.0a4/Lib/wsgiref/handlers.py", line
199, in write
    self.send_headers()
  File "/home/delimy/temp/Python-3.0a4/Lib/wsgiref/handlers.py", line
255, in send_headers
    self.send_preamble()
  File "/home/delimy/temp/Python-3.0a4/Lib/wsgiref/handlers.py", line
178, in send_preamble
    self._write('HTTP/%s %s\r\n' % (self.http_version,self.status))
  File "/home/delimy/temp/Python-3.0a4/Lib/wsgiref/handlers.py", line
385, in _write
    self.stdout.write(data)
  File "/home/delimy/temp/Python-3.0a4/Lib/socket.py", line 222, in write
    return self._sock.send(b)
TypeError: send() argument 1 must be bytes or read-only buffer, not str

It should convert str to bytes before write to stdout.