dunno, their scripts that build the systems are hosed, but manually going through most of the setup steps fixed it all. SP completely relies on IP/Hostname info, as well as interface type. If you change the primary interface, then you bork the whole thing and it's a few hours to fix it up, assuming you want to re-install the nodes. I never did figure out kerberos' problem, even with rebuilding it's database. Only a node reinstall fixed it.
still... 2 classes over 3 weeks and they never got it working just right. the other guys have run into minor problems, but prior to having the old C20 machines brought in, theirs didn't work either.