Python Exception Occurred

Traceback (most recent call last):
  File "/home/rizwank/geekymedia.com/viewcvs/lib/viewcvs.py", line 2625, in run_cgi
    main()
  File "/home/rizwank/geekymedia.com/viewcvs/lib/viewcvs.py", line 2600, in main
    view_log(request)
  File "/home/rizwank/geekymedia.com/viewcvs/lib/viewcvs.py", line 1708, in view_log
    read_log(full_name, None, view_tag, query_dict['logsort'])
  File "/home/rizwank/geekymedia.com/viewcvs/lib/viewcvs.py", line 1466, in read_log
    idx = string.rfind(head, '.')
  File "/usr/lib/python2.7/string.py", line 376, in rfind
    return s.rfind(*args)
AttributeError: 'NoneType' object has no attribute 'rfind'