This isn't a bug yourev - 9 times out of 10, an update for Supremacy will break compatibility with your saved games. Your saved game relies on a specific set of files being present in the game. But since you've performed an update, those files have either been deleted, renamed, or changed/updated. When you try to load your save file, it can't load them because of those changes, and the game crashes.
I'm sorry if it was a save that you've been playing for a long time, but i'm afraid you won't ever be able to use that saved game again - you're going to have to delete it, along with all of the other saves you've already got. Chances are you'll have to do that every time the game is updated.
Still, I hope you like the changes that Mike has made with this update. You can play as the other Empires now.
_________________"Anyone without a sense of humour is truly at the mercy of the rest of us."