I don't know about the ring heroes. I had played them all without crashing except on one which I think was fixed for the release(Gil Galad, don't remember if I did fix him on time for the release). Which one is crashing when you try it?
I have tried to make ring heros of Men, Elves, Mordor, Isengard.
Only Elves works right.
For earlier version, I wouldn't face this problem.