I only posted here because the vBulletin guys told me they were absolutely sure the problem is due to my PhotoPost add-on. I had to ask if there was something I needed to do with PhotoPost when I upgraded vBulletin.
Like I said, I'm not a programmer, but I believe that it is a vBulletin issue, not a PhotoPost issue. Simple logic. I had no problems until I upgraded vBulletin. I voiced my frustration here, but I'm not pointing blame at PhotoPost. I'm quite satisfied with your response and will continue to look at vBulletin for the source of the problem.
Thank you for your time.