Mod_python error: "PythonHandler main"

Traceback (most recent call last):

  File "/usr/lib/python2.3/site-packages/mod_python/apache.py", line 193, in Dispatch
    result = object(req)

  File "/home/seb/public_html/main.py", line 1290, in handler
    full_uk_from_date = uk_date.mysql_to_full_uk_date_only(viewTheEvent_from_date)

UnboundLocalError: local variable 'viewTheEvent_from_date' referenced before assignment