It's actually rule 408. Sorry about the typo in the above post. Keep in mind, that Fox made those allegations in their lawsuit. They may or may not be true. But if true, I am not sure why any of it would affect the prohibition against using settlement negotiations in court. I would think that in order to settle the claim, FOX would want detail the allegations in any Waiver or Release. So at some point during the settlement process, names dates etc. would have to be exchanged. Just because it hadn't happened (according to Fox) doesn't mean it wouldn't have, if Fox were negotiating in good faith.
Okay. It just seemed like their initial approach was "one of your big guys (and we're not saying who) did some bad stuff. Give us 60M or we're going to sue."
That screams extortion - and IIRC, extortion is illegal even if the action you threaten (suing) is otherwise perfectly legal.