Yep, that is bad programming. You don’t just allow a variable to divide by another without protecting against the dreaded divide by zero. However, that variable is probably coming from the bone lengths. Did you alter bones or make one have a zero length?
thanks for the hint but I suppose that this isn’t the problem because I tried two different skeletons without success.
I’ll check it again. Maybe it has something to do with the mesh?! I’m not sure…