Waaah! I had the same problem 0_0
or like the main.system error...

what I did:
I asked a friend to make a copy of her save files and used the save file right BEFORE
the first choice because the game wouldn't crash then and I never had an error after that : D

if anyone wants a save file like that, ask me ne I'd be happy to help!

And uhm always make sure to pick the full installation option ne ^^;;