The problem you're having with the game shutting down completely, not just loading, as that is what Ouka addressed, can be solved in a number of ways.
Firstly, make sure you're placing the file into the exports folder. If that is what you're doing, try this route instead;
Place the fhm. file in the terrains file under media (also located in the Feral Heart folder). Place all fho. files into my_objects, under objects in the media file. Sky and weather files go into the sky folder under media.
If this is only one map you've tried and have problems with, it could possibly be the map, I know I had problems with one of my own maps because something didn't export correctly. So be sure to check with other members of the roleplay to see if they have similar problems.