I had the exact same problem after trying to upgrade Moveable Type — my blog “broke” and I was no longer able to get into the admin system, even after trying to “re-upgrade”. I was able to get a backup of the MySQL database, however, and found this post by Googling for a way to import from the MySQL dump. Unfortunately, I didn’t find one.
I ended up creating a fresh install of Moveable Type in a different location — absolutely no “overlapping” files. I created a completely new database, then completed the MT installation. I then imported my SQL dump into the new database and finally used MT to export my old blog entries so that they could be imported into WordPress.
It sounds tedious, but actually only took 20-30 minutes. Granted, that’s far too long when Moveable Type is the culprit but it worked.
