It's not perfect, but these patches have revived MT Blacklist on my Windows server enough to allow me to block comments effectively once more. I still get several error screens interacting with it, but I was able to add enough items to the blacklist that most of my spam has been cutoff.

The patches are bit cumbersome. There are bugs in MovableType 3.x itself that need to be fixed, which is perhaps one cause of the perpetual delay in getting out an official version of MT Blacklist for Windows. If you can put up with the spam, the fixes will appear in the next MovableType release.