This is a fairly big issue that a lot of people are happening, yet GTP isn't really paying any attention.
It has something to do with the PSN and being signed in while trying to play. You CANNOT be signed into the PSN while playing, otherwise the game 'freezes' while trying to connect to the PD servers. I've done everything I possibly can to fix it. Reinstalled four times using different methods(Patch first, patch after, patch after install and then install again, etc), none of them have helped. I've deleted my actual save game data after saving it to a USB drive, that didn't help at all either.
I cannot play online, nor can I access any of the online features or events, nor can I play GT5 while signed into the PSN at all. I've refreshed my IP, messed with my network settings, etc. I can still play other games online, so it's a GT5-only problem.
This is on a brand new 160gig slim. I doubt it's the system, but something to do with the servers. Been this way since the update came out.