Hmm... unfortunately, I only have Outlook 2000, which does not include the SenderEmailAddress property new to 2003. However, I do know that extracting any types of email addresses in Outlook 2000 is an absolute pain in the rear, as a security update by Microsoft prevents access to any email address properties without explicit confirmation in the form of a run-time popup. I'd be surprised if Microsoft had actually removed that restriction in 2003, and it might be possible the restrictions on this property are hindering your loop.

To test it, try commenting out any lines which reference the SenderEmailAddress property, and set strDomain to a constant string such as "vbaexpress.com". Add or change a Debug.Print line to display only olItem.Subject, and then run your script. What the Debug.Print line sends to the Immediate window might give you a clue as to what items it's running the loop against.