I've had this error for a week or two now, and I've been able to get along without rebuilding my Individual and Category archives, but I'd rather not have the error there. Not only did it appear out of nowhere -- I was just doing a normal rebuild after editing my templates -- but it also specifies nothing. In fact, I have reason to believe that the actual error message is an error because it pops up with the text "An error occurred", and then an empty red box where the message would actually be. However, I still can't rebuild more than my indexes, and it's worrisome.

If it helps, in the last few weeks, I've been messing around with Akismet and SpamLookup settings (sick of nasty comments and trackbacks) and today, I'm just messing with trackbacks and templates. Any help would be greatly appreciated! Thanks

This is tedious, but generally the best way to figure these out:

Start by completely blanking out your individual archives and doing a rebuild. Then blank out the category archives, and so on down the line, until you don't get the error anymore. Then start putting things back in until it happens again. The last thing you add back will be the source of the problem.

At that point, take that template, and basically repeat this process, except by taking out chunks of just that template. Occasionally it'll be something as dumb as a miscapitalized tag.

I tried blanking out all of the files I've touched in the past week or two, and nothing's worked so far. Lemme try repairing my database. Hopefully it's not something that I'll have to reinstall MT for -- that would stink.

But thanks for your advice!