I had this problem too for quite a moment. You're probably on a 32 bit version, so it's already known.
Here's the topic that helped me to start the game (the loadings are still a bit slow but it do work now) :
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=477192&an=

Come from the flames, burn in the fame.