Entourage rules not working automatically
 

I'm not sure if anybody can help on this one. For some reason, Entourage has decided to stop automatically applying rules to my incoming mail. I can select the message once it has come in and apply an individual rule (Message > Apply Rules > Rule X). But if I select the message and try to apply ALL rules (Message > Apply Rules > Apply All Rules), nothing happens.

I purged old messages and rebuilt the database, but that didn't help. Any suggestions.