AttributeError: 'NoneType' object has no attribute 'write_cmds'

2011-04-19 22:05:07,321 [ERROR][asynctaskreplyqueue] __fetch() @ consumer.py:90 - asynctaskreplyqueue
Traceback (most recent call last):
File "/usr/lib/python2.6/site-packages/gofer/messaging/consumer.py", line 86, in __fetch
return self.receiver.fetch(timeout=self.WAIT)
File "<string>", line 6, in fetch
File "/usr/lib/python2.6/site-packages/qpid/messaging/endpoints.py", line 994, in fetch
self._ecwait(lambda: self.linked)
File "/usr/lib/python2.6/site-packages/qpid/messaging/endpoints.py", line 50, in _ecwait
result = self._ewait(lambda: self.closed or predicate(), timeout)
File "/usr/lib/python2.6/site-packages/qpid/messaging/endpoints.py", line 957, in _ewait
result = self.session._ewait(lambda: self.error or predicate(), timeout)
File "/usr/lib/python2.6/site-packages/qpid/messaging/endpoints.py", line 550, in _ewait
result = self.connection._ewait(lambda: self.error or predicate(), timeout)
File "/usr/lib/python2.6/site-packages/qpid/messaging/endpoints.py", line 194, in _ewait
self.check_error()
File "/usr/lib/python2.6/site-packages/qpid/messaging/endpoints.py", line 187, in check_error
raise self.error
InternalError: Traceback (most recent call last):
File "/usr/lib/python2.6/site-packages/qpid/messaging/driver.py", line 496, in dispatch
self.engine.dispatch()
File "/usr/lib/python2.6/site-packages/qpid/messaging/driver.py", line 791, in dispatch
self.attach(ssn)
File "/usr/lib/python2.6/site-packages/qpid/messaging/driver.py", line 834, in attach
self.link(rcv, self._in, rcv.source)
File "/usr/lib/python2.6/site-packages/qpid/messaging/driver.py", line 885, in link
dir.do_unlink(sst, lnk, _lnk)
File "/usr/lib/python2.6/site-packages/qpid/messaging/driver.py", line 261, in do_unlink
sst.write_cmds(cmds, action)
AttributeError: 'NoneType' object has no attribute 'write_cmds'