Oh, I've had this problem before and I managed to fix it without reinstalling FH, then again I also had FH backup files, so that helped me as well. Uhm, if you need the file in question, I might be able to give you one of my copies of it. Your crash is happening as soon as you click on map maker, correct? If that is so, then your temp.map file might be corrupt. Once again, this is an easy fix and I can give you a backup file if you want me to. When you get the backup file you will just need to place it into terrains which is located in, FH > Media > Terrains. Do that and it should stop crashing.