Evtl. hilft euch das für die Freischaltung von dem Content der Limited Edition auf dem PC:

Crysis 2 wont remember my multiplayer key
1. 1. Load Crysis 2, go to multiplayer and type in your key
2. Navigate back to Single Player
3. Go back into multiplayer and re-enter your key

My limited edition promo code doesn’t work
Some users were experiencing a corrupted login when visiting MyCrysis.com to redeem their promo code. This corrupted login was preventing them from being able to redeem their code properly. To correct this problem, the auto-login function has been disabled.
Before you may redeem your code, you will have to re-enter your MyCrysis login credentials. You must login with your registered e-mail address, not your username.
If you have already tried to redeem your code unsuccessfully, you will have to delete your browser cookies before you may successfully login and redeem your code. Deleting your cookies should clear any corrupted login data from your browser and allow you to proceed with code redemption.
Das Kam zumindestens vorhin von Crytek via eMail!