It's BS. It always has been. The game's such crap it just shuts itself down. Either that, or the crap from the forums has spilt over into the game's MP creating a super nexus of online BS that results in the servers shutting down and being reactivated SOON™!
Time for new games baby! Abandon ship!
"Dann singe ich ein lied fur dich"
You won't find me playing U3 much any more, so I didn't come across this problem. Starhawk is what I play now, multiplayer edition for $20 on the ps store.
Too expensive for my taste.