im having this problem too, it was fine when i played it 2 nights ago, then suddenly went to play it yesterday and i go to load my saved game but halfway through trying to load it, windows comes up with an error and closes it, also xfire shows me an error, doesnt say what caused it or anything though. i play with heaps of mods yeah, on a copy i bought but i use the no cd crack to mod.. havent had any trouble before with them so its real strange and cold turkey like for it to just not work like this.
today i tried reinstalling but same thing.