Check you AIW, that'll be one of the last things to load. I think the load order is textures, geometry, AIW and HAT/HAT rebuild. The last two can be in different order but usually if it crashes at the end, i need to check AIW. BTB can do export errors, they are rare but they do happen. A simple refresh might do the trick, open AIW menu in the BTB, that'll refresh the waypoints. Or check the AIW with guitarmans editor.