I'm finally reinstalling the blog software tonight to solve the errors, also upgrading to Movable Type 3.3. I'm suspending commenting for a while so things don't disappear when I input the backup. After that I'll still be tweaking things and probably adding a captcha or other form of spam control. Maybe a chess version of kittenauth?! I'm currently being bombarded with several hundred comment spams per day. The filter catches 99.5%, but the load is notable.
When I'm done with the major lifting I'll post an all-clear here and turn commenting back on. Then you can notify me of problems you find. I'll be updating the templates as well, but that's not critical and will take a few days. If the whole thing goes down and you get 404 errors, sorry. Thanks for your exasperation.
Update: As you can see, things didn't go too well on the data front. The data corruption that was causing the errors we were experiencing made it impossible to correctly export it all, starting on June 1. I'm apparently going to have to reenter every entry since them, but that doesn't include comments. I can manually insert links to my backup pages for each entry from June to now, which sounds rather hellish and won't be my top priority today. The good news is that the back-end is doing great, much faster and more stable now on MySQL.
Update 2: Found a fairly fast way to reenter two months worth of blog thanks to the mightiest utility in the land, Clipmate. Powerpaste rocks. I think I've also come up with a lesser evil way to get the comments back for June-July. No, not entering all 2000+ of them into the system one at a time. But pasting them into the "extended" entry field will at least make them available. Not sure what they'll look like just yet but at least they'll be readily available and new comments will appear below them in a fairly natural way.
Update 3: Okay, all the comments are back for June-July, slapped into the extended entry and without formatting. Commenting is also back on. Now to the templates so the item pages look right. I'll get to the search and monthly archive templates later. At least the admin is three times faster than it was before. I'll also be doing categories and tags in a few days. There are probably some broken links and such. Post issues and bugs here.
Update 4: Seems like all is well, although I need to import the notification list somehow. Any bloggers out there want to test out the trackback system with this item?