unexpected "sample larger than population" error

[NorthIsUp]

(2012-10-09 14:25:19,751 [INFO] extensions) Subscribing to Channel(realertime.all, engine=<chattr.io.engines.kafka.KafkaEngine object at 0x107f00d50>, versions={})
Traceback (most recent call last):
  File "/Users/adam/.virtualenvs/realertime/lib/python2.7/site-packages/gevent/greenlet.py", line 390, in run
    result = self._run(*self.args, **self.kwargs)
  File "/Users/adam/Documents/sandbox/disqus-service/src/disqus/service/concurrency.py", line 33, in _run
    self.target(*self.args, **self.kwargs)
  File "/Users/adam/Documents/sandbox/disqus-service/src/disqus/service/application/extensions.py", line 87, in subscribe
    map(self.__handle_message, self.listen_to)
  File "/Users/adam/Documents/sandbox/chattr.io/client/src/chattr/io/models.py", line 72, in next
    raw_data = self.__delegate('next', block)
  File "/Users/adam/Documents/sandbox/chattr.io/client/src/chattr/io/models.py", line 63, in __delegate
    return getattr(self.__engine, method)(self.name, *args, **kwargs)
  File "/Users/adam/Documents/sandbox/chattr.io/client/src/chattr/io/engines/kafka.py", line 31, in next
    return self.iterator(channel_name).next()                                                                                                  
  File "/Users/adam/.virtualenvs/realertime/lib/python2.7/site-packages/samsa/consumer/consumer.py", line 142, in __iter__
    msg = self.next_message(self.config['consumer_timeout'])
  File "/Users/adam/.virtualenvs/realertime/lib/python2.7/site-packages/samsa/consumer/consumer.py", line 152, in next_message
    return random.sample(self.partitions, 1)[0].next_message(timeout)
  File "/usr/local/Cellar/python/2.7.3/Frameworks/Python.framework/Versions/2.7/lib/python2.7/random.py", line 320, in sample
    raise ValueError("sample larger than population")
ValueError: sample larger than population
<GeventThread at 0x107ed9410> failed with ValueError

[NorthIsUp]

recovered after a few minutes, but lost offset information