BF 2142 Registration with Origin

The account name and password for Battlefield 2142 are Classic EA account names and they're different from your Origin account details even though they should be linked to your Origin account.  When Battlefield 2142 launches, click the option to be emailed your account name and you may have to also click to change your classic EA account password as well.  If you never created a classic EA account, then you'll have to create one, but since it sounds like you repurchased the game, then that sounds like you've already played it, so you may already have one.

If you already have one, and you're getting that error, it may indicate that your classic EA account is tied to a different Origin account than the one through which you downloaded the game and you might have to set up a chat or callback through help.ea.com to get that all worked out.