EA discontinued the online pass. You don't need it to play online anymore.
The same problem here. "An Online Pass is required to activate online features ..." keep rolling on the right.
When I select Purchase Online Pass Code, an empty PlayStation Store appears.
I can download Online pass from the PSN store (ME3 game folder), outside the game. However nothig changes in the game itself. "An Online Pass is required ..." still there.
I have found root cause of my problem. I purchased game in store located in Europe, but game media I got was marked for Region 1 BLUS (USA + Canada).
My PSN account is European, therefore game online content didn't work. I returned game to retailer.
More about Playstation regions here http://community.eu.playstation.com/t5/Gaming-Network-Support/Important-info-regarding-PS3-game-regions-codes-and-DLC/td-p/19920601
