The first suggestion is what we've heard already: delete your game cache and save data. However, other parts to the laborious process include disabling internet connectivity on the system. Then, disabling the Information Board, Media Server, screen aver, and more. When your PS3 is totally gimped, it may be able to successfully play Grand Theft Auto IV.
Sorry, but that's not going to cut the mustard. We're sure that the people affected by this mysterious plague of errors want a patch -- one that allows them to play the game without disabling every feature of their PS3.