Just FYI, I traced my "bug" all the way back to the original installation of 4.07 from the game CD. I keep that version on my hard drive so I don't have to reinstall from the CD should I need to. Anyway, I uninstalled it and then re-installed it and the "bug" persists. My optical drives are fairly new and top line drives, so I'm going to assume the problem is in the game CD itself. So I've ordered a new one.
