Runtime errors usually are caused by a disk-full error. So check if the rebuilder destination or the cmpro temp path is full. Or maybe it's a corrupt zipfile on disk and ClrMamePro's zipreader tries to fix it automatically (which fails of course...but that shouldn't cause a rterror..hmm...) ...or try to remove/disable the demontools.

Roman Scherzer
ClrMamePro