No error messages or anything? Just the program becomes non-responsive?
Have you tried to open the level in gmax and see if gmax has a baby as well?
Have you tried to install another copy of 3ds on your pc?
You see Maarten, the more specific, the less questions get chunked onto you.
_________________
I am sorry to report I have destabilized the relative speed of some photons, which caused an immediate singularity to form. Then, the singularity pulled itself away from the space-time continuum and destroyed a local trailer park. I hope my insurance covers this.