When you create a rule in Outlook 2003, it's often marked 'For this machine only' this means the rule is a client side rule and will only run on the machine it was created on. This prevents rules from being automatically disabled when the rule fails after opening an Exchange mailbox from another computer.

Since POP3 and IMAP rules are client side only and not stored in the mailbox online, this setting won’t have any effect on your account, but the condition "for this machine only" is added to every rule anyway.