Hey ... how do you think I was feeling?
Anyhow, to make a long story short ...
* PHP was reconfigured on the Web server in a way that prevented new messages from being posted to the Cyburbia Forums. You could still read messages, but you couldn't post. (Cyburbia was hosted for free, but it was on a dedicated server that really wasn't intended to function as a commercial Web site hosting service. Unfortunately, vBulletin couldn't function properly given the server's very high security configuration.)
* Last Friday, I reluctantly moved Cyburbia to a private Web hosting service. The name change propagated slowly throughout the Internet. For about 48 hours some folks were getting the "old" Cyburbia, while others were getting the "new" Cyburbia ...
* ... which was even more screwed up, because people were getting "cybubria.org is not permitted to access this database" errors when they accessed the forums.
* Last night (after working from 8:00 AM to 11:00 PM -- this will be a 70 hour week, I fear), when I got home, I spent a couple of hours researching the problem with the Forums on the "new" Cyburbia, and what to do. The answer was simple -- change one line in a vBulletin congifuration file.
Joy! All better now. Not just that, but file and avatar uploads are also working again -- something that stopped a couple of weeks ago.
Sorry for the interruption. Hopefully there won't be any snags in the near future.