Y'all, it's apparently a randomly occurring problem on the back end of the forum. Tech support has looked at all the likely areas, but can't find the reason. This forum software is old and slated for replacement in the not-too-distant future, so I'm not sure how much effort will be put into trying to resolve this.
I'm sorry about the loss of posts. I know it's a big hassle, especially when you're dealing with a sick pig, or when you've got a lot of useful posts that people rely on. Spy9doc lost thousands of posts, several of which I had bookmarked and referred to a lot because they were so useful. The only good thing I can say about it is that it's only happened a very few times that I know of, so maybe it won't happen again until the software is upgraded.