Why do these things always happen when I'm away?
Apparently we had a problem in the forum table that logs who is online, and I had to sign into the database to fix it. It only took me a few minutes to do the maintenance, but unfortunately I was away from any computers since yesterday afternoon, so I didn't know there was a problem until I checked my email a little while ago.
My thanks to everyone who alerted me to the problem. I haven't even read them yet (just seeing all of them made me jump to the site to find out what was going on!), but I will be replying to them.
And by the way - HAPPY THANKSGIVING EVERYBODY!