An error occurredFun stuff, I tells ya. Hopefully, I'll figure something out, but in the mean time, you may see some strange stuff on the individual entry pages (particularly with respect to the comments, as that seems to be where the problem is localized.)
Can't call method "created_on" on an undefined value at lib/MT/Template/ContextHandlers.pm line 3764.
Update: Very little progress made. The comments are definitely what's causing the problem. When I remove the code that generates the list of comments, the individual entry archives rebuild fine. When I try to add it back in, bit by bit, I start getting http 500 errors or the original error I was getting above. Somehow, the most recent 30 entries or so have had their comments restored. Beyond that, there's a lot of older entries that have comments, but those comments aren't being displayed because I can't rebuild them without manually rebuilding each entry individually. So if you're on an old entry and you see "Testing something" where the comments would normally be, don't worry. The comments are still in the system, but I can't seem to publish them...