[Spambayes] Not Auto Filtering Messages

[Dolvig Andrew-ra8839]

Anyone,
   I am running Spambayes 1.0rc2 on my Oulook Express at my office. When I initially set up the system it would filter my messages as they arrived. I fell in love with the system as it kept me from deleting ~50 messages a day of SPAM.  Recently, and I am not sure why, the system is no longer filtering the messages as they arrive. I can still manually go to FILTER MESSAGES and it will work great, but it does not filter the messages as they arrive. I have tried to toggle the ENABLE BACKROUND FILTERING button in the advance setup section, but that has not seemed to make a difference.  I would appreciate any help that you can provide me.
      thanks,
            Andrew