We've just been told from a PS3 dev source that the WipEout HD locking problem is "definitely a friends list issue, not an SDK bug. It can be coded around, so there's bound to be an imminent patch."
As previously reported, people with more than 50 friends on their PS3 lists are getting lock-ups with the game.
SCEA said overnight it's looking into the problem. Sounds as though it isn't anything too heavy, so expect it to be fixed soon.