Hmm, I may have the problem with the latest install. I think some of the files ended up in \Black Isle\BGII-SOA instead of \Black Isle\BGII - SOA. Still not sure what was up the first time. Well, here I go again.
Interesting. Reinstalling without any optional components solved the problem. The interesting part is that the menus have changed slightly. Background pictures, menu text, and so on. Well, whatever, it works.
Huh, I'll give it a try, thanks. It can't get any worse after all. I could have sworn I did everything right, but I don't have any better ideas, and nothing but time, so it's worth a shot.