Just some first thoughts
1. Make sure it's a poly object
2. Make sure none of the coordinates are locked...just a thought.
3. Since it happened after you UV mapped, try applying an automatic map to see if it fixes the problem. If it does, you could then try mapping it the way want and hopefully it won't crash again.
Don't be satisfied with what you can do but rather strive to do the things you can't do!
Exceed Expectations!