In my first post i said i thought it was a memory problem. Today i did some testing and i found out that playing the game for half an hour or so, then save and reboot the ps3, makes it playable. It obviously resets the ram and so it is playable again.
In another topic i found a comment of a reader who said the ram gets a reset when you quit the game and the load a save again. So a reboot is not needed cause when you close the game it is programmed in a way it clears the ram.
Haven't done it like this yet so you should try.
Furthermore, Hines confirmed on his twitter they are working on a patch so maybe this temporary workaround can make it playable.... I'm counting myself lucky not to be able to play for a few days

I hope the patch is ready next week...
And also, please don't go out and buy SSD disks, it does not work. Especially with those craze prices right now....