[endgame]

Guys, I don't know all of your particulars, but I'd suggest that you uninstall the game, delete everything related to OOTP. I'm not sure that I wouldn't even delete your Saved Games directory, if you've carried one over at all, but it wouldn't be mandatory at this point. Also, after you "think" you've deleted everything, go to your Start menu, or whatever it's called on a Mac, Run %appdata% and delete Out of the Park directories and any SI Interactive directories that may be present there. This should allow you to do a fresh install of the game and see if you get the same error.