Error in calculate_updates task

[mejymejy]

Found this in the celery log on the server:

[2013-10-10 17:02:46,957: ERROR/MainProcess] Task bamboo.core.calculator.calculate_updates[ba0045a9-ef65-40a2-a2e0-e80264c443e0] raised exception: TypeError("'NoneType' object has no attribute '__getitem__'",)
Traceback (most recent call last):
  File "/home/bamboo/.virtualenvs/bamboo/local/lib/python2.7/site-packages/celery/task/trace.py", line 228, in trace_task
    R = retval = fun(*args, **kwargs)
  File "/home/bamboo/.virtualenvs/bamboo/local/lib/python2.7/site-packages/celery/task/trace.py", line 415, in __protected_call__
    return self.run(*args, **kwargs)
  File "/var/www/bamboo/current/bamboo/core/calculator.py", line 77, in calculate_updates
    __ensure_ready(dataset, update_id)
  File "/var/www/bamboo/current/bamboo/core/calculator.py", line 240, in __ensure_ready
    update_id and dataset.has_pending_updates(update_id)):
  File "/var/www/bamboo/current/bamboo/models/dataset.py", line 429, in has_pending_updates
    pending_updates = self.pending_updates
  File "/var/www/bamboo/current/bamboo/models/dataset.py", line 165, in pending_updates
    return self.record[self.PENDING_UPDATES]
TypeError: 'NoneType' object has no attribute '__getitem__'