An Exception Has Occurred

Python Traceback

Traceback (most recent call last):
  File "/usr/lib/viewvc/lib/viewvc.py", line 4322, in main
    request.run_viewvc()
  File "/usr/lib/viewvc/lib/viewvc.py", line 397, in run_viewvc
    self.view_func(self)
  File "/usr/lib/viewvc/lib/viewvc.py", line 3414, in view_revision
    rev = request.repos._getrev(query_dict.get('revision'))
AttributeError: 'NoneType' object has no attribute '_getrev'