Happened to me too, to fix this do this
When you are un main menu, press "X" in MP option and then inmediatly PS Home button, the XMB should appear while the loading online screen is in background, wait some seconds (or wait 'till the loading bar reset or the section of the bar are that freezes be passed )and press the PS Home button again, the message: "The Facebook features on the PS3 system are no longer avaible" appear and you are good to go
Here 2 videos that i followed, better follow them just in case
And Naughty Dog fix this!
Many thanks Daniel for this post.
I've got this problem since 2 days now, I've posted several question ....without answer.
I just read your post this morning,
I do what you explained and............. Miracle...It Work Well !!!!!!!!!!!!!
Many thank Guy !!!
I special Pint of beer from south of france for you !!! ;-)))