I have not have problems my but my friend has, we have since the launch and he hasn't been able to do anything until now, and what seemed to fix it is deleting the title update and redownloading it. he has tried over and over again for hours on end waiting for players to join, remaking characters, all that. This made it work the very first time and we are in a game right now as I type this post. I hope this helps anybody having issues, not that it is not a guaranteed fix, but it seems to have produced a definite result.
Delete Title update, redownload/reinstall title update
Edit: Forgot to mention, this was on Xbox 360. Sorry guys, but I can't say because I don't have a PS3, where you find the files to remove on PS3 I do not know.