So wait, once you get the error message you don't stop getting it or something?
It is apparently an issue with Activision games' authentication server(s). It is dropping legitimate IDs and then they CAN NO LONGER GO ONLINE WITH THEM! This is affecting all Activision games on PS3, not just BO2.
Once you get it you keep it forever . . . like luggage. They are trying to fix the issue but No ETA on a fix just yet.
This just happened to me today BTW and it sucks! I was just starting to get into the the groove with this game.
You can't talk to a Psycho like a normal human being Mothers are trails on stars in the night, Fathers are black holes that suck up the light.