Also, the way I understand it (correct me if I'm wrong), Penn State took the Freeh Report and handed it to the NCAA and said, "We are using this to self-report what we have done wrong". So the NCAA says, "Okie dokie," then they hummed the "Jeopardy" theme a few times while they read the report. "If Penn State agrees with this, we shouldn't waste our time pushing on a rope," the NCAA decided, and came up with the sanctions based on what Penn State self-reported.
I can see suing the NCAA that the sanctions were too severe, but as exhawg pointed out, Penn State already accepted the sanctions without a fight. I think that the only ones the Paternos can be upset with is Penn State. Maybe this Louis Freeh guy - but the fact that Penn State accepted the report actually makes it their responsibility, and not so much Freeh's.