Rules only work when I first start Outlook 2003

[Terry]

Hi all. I have a problem with my rules in Outlook 2003.

I've upgraded from OL XP, and now my rules only seem to work when I first
start up OL 2003 and it checks my mail.

I'm using several POP accounts and I want the mails moved to specific
folders depending on the mail account they come in on. The rules worked fine
when I was running OL XP, but now they only run on the first mail check as
soon as I open OL. Any subsequent mail checks, either automatic (every 5
mins) or manual just sends any new mail to the Inbox.

I have read about an OL prob where the rules don't work on the first mail
check, but they work on subsequent checks. My problem seems like the
opposite?!

The rules work if I run them manually with "Run Rules Now"

I have tried the following to no avail:

created a new OL 2003 pst and imported all my mails
deleted and re-created the rules
added "Stop processing rules" at the end of relevant rules

I can't seem to find any updates for OL 2003 on the MS site. If I do a Check
for Updates it comes up with some downloads for Office XP, but I'm running
Office 2003 Pro?! Do I need to uninstall and do a full install of Office?

Thanks in advance...

Terry