This is due to a not properly working crack, both located on GCW do not work the way they actually should.
If it doesnt crash when creating a character (Did happen over here, too), then the controls will go mad, you cant leave cars, ...
Only way to avoid this is using a mini image, using winXP compression (to make it about 3 GB smaller, quite good
-> ~300kb )
However, just mount and use SD4Hide or ProtStop if necessary
Good luck, mate
// lol, youre using safedisc to hide your drives ?