I'm almost positive that a feed the beast pack would not ship with bad config files. I was more thinking that if you changed any configs, it would be worthwhile to look them over. If you haven't changed anything, then it might not even be a problem with the config files. I could not find a lot of information on these types of crashes. Sorry I don't have a specific solution.
Edit: have you tried redownloading the pack?
Edit 2: The link I gave also send to suggests that they have had that error when the server configs were messed up.