ProtocolError: Got unexpected 'OK'

What steps will reproduce the problem?
1. Play songs
2. Replace current play list with a new album

PHP 5.3.2-1ubuntu4.18
Firefox 18.0.2
MPD 0.15.4

Often when I replace a playlist I get

500 Internal Server Error

The server encountered an unexpected condition which prevented it from 
fulfilling the request.

Traceback (most recent call last):
  File "/home/ddula/usr/src/python/client175-read-only/cherrypy/_cprequest.py", line 606, in respond
    cherrypy.response.body = self.handler()
  File "/home/ddula/usr/src/python/client175-read-only/cherrypy/_cpdispatch.py", line 25, in __call__
    return self.callable(*self.args, **self.kwargs)
  File "./server.py", line 146, in add
    mpd.findadd(args[0], args[1])
  File "/home/ddula/usr/src/python/client175-read-only/mpd_proxy2.py", line 262, in findadd
    self.command_list_end()
  File "/home/ddula/usr/src/python/client175-read-only/mpd_proxy2.py", line 196, in command_list_end
    return self.con.command_list_end()
  File "/home/ddula/usr/src/python/client175-read-only/mpd.py", line 451, in command_list_end
    return self._fetch_command_list()
  File "/home/ddula/usr/src/python/client175-read-only/mpd.py", line 362, in _fetch_command_list
    return self._wrap_iterator(self._read_command_list())
  File "/home/ddula/usr/src/python/client175-read-only/mpd.py", line 294, in _wrap_iterator
    return list(iterator)
  File "/home/ddula/usr/src/python/client175-read-only/mpd.py", line 287, in _read_command_list
    yield retval()
  File "/home/ddula/usr/src/python/client175-read-only/mpd.py", line 298, in _fetch_nothing
    line = self._read_line()
  File "/home/ddula/usr/src/python/client175-read-only/mpd.py", line 239, in _read_line
    raise ProtocolError("Got unexpected '%s'" % SUCCESS)
ProtocolError: Got unexpected 'OK'

MPD LOG

Feb 09 20:41 : client: [0] process command list returned 0
Feb 09 20:41 : client: [0] process command "clear"
Feb 09 20:41 : playlist: stop
Feb 09 20:41 : output: closed plugin=alsa name="My ALSA Device"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [0] process command "stats"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [0] process command "status"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [0] process command "stats"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [2] opened from 192.168.x.x:38158
Feb 09 20:41 : client: [1] closed
Feb 09 20:41 : client: [2] process command "tagtypes"
Feb 09 20:41 : client: [2] command returned 0
Feb 09 20:41 : client: [0] process command "stats"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [0] process command "status"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [0] process command "stats"
Feb 09 20:41 : client: [0] command returned 0
Feb 09 20:41 : client: [0] process command "play "0""
Feb 09 20:41 : client: [0] command returned -1
Original issue reported on code.google.com by d...@documentopia.com on 10 Feb 2013 at 1:42
martinanton / client175

ProtocolError: Got unexpected 'OK' #47
