347 leafs... that shouldn't cause any problems, the map isn't really big or complex. My recent map had 11000...
I don't really know why it is frozen, does it happen in any other map compiles?
Were there any errors in the compile log before the rad procces?
Describ the map, maybe we can understand whats causing the problem if you'll give us a short discription of the map.
By the way when Barttylord asked you to look in the task manager he ment that you should check the procceses tab.(the procces is called Hlrad, If it's working and taking all the CPU that means you might need to wait more)