I have same problems sometimes, i have not isolated what the cause is. It's strange in that it's not a universal thing. I tried one terrain i made using the S&D tool to import the terrain, and it crashed, one with AKWabbit's tool it worked fine, another it didn't. I haven't tried one using niether, as my computer's processor power is too low end to make one from scratch in a reasonable amount of time. ( my frame rate goes to hell after i get about 1.5 sectors of terrain/elevation put in. ) still toying with it tho, as i have plans for H2H dueling terrains, and some real-world terrains that didn't see anything in the way of world war 2 action, but would be neat to do some "fantasy what if?" scenarios on. I'll keep working on finding out what causes that crash tho and post if i find it.
Hamish!