Something catastrophic happened to the database Monday afternoon (12/3/07), apparently shortly after the last time I was on the site. I didn't even realize the site had gone down until Moron4392 emailed me yesterday morning. When I checked I discovered that I could not access the database through any of the methods available to me, so I had to call for help.
I still don't know for sure what happened, but the hosting company's tech guys had to rebuild the database and create a new login, etc, on a different server. I'll do another local backup at home tonight, although having a local copy didn't help me in this case, since I couldn't even access the database in order to fix it.
On a side note, I am in the process of choosing a new hosting service, and the site will probably be getting moved to a new server over the Christmas holidays. I'll post more information in a new announcement once I have more details.