Rules run manually but not automatically
 

I am using Outlook 2003 with all the latest updates on XP with SP2. I have
several rules with very short names to delete messages with a certain
subject line. The rules will run if I click Run Rules Now, but they don't
work unless I do that. I searched high and low, and found lots and lots of
people with the same problem, but no one with a solution. Does anyone have
any helpful hints to resolve this problem? Thanks