I have the exact same problem I entered the key getting the "This product key is already active, it cannot be used again." error message and nothing shows up on my account for open beta besides the uniform code I entered earlier from movie box. My husband put his keys in and shows pre-order and closed beta access nothing shows for open beta.
Yes, Fileplanet. They giving out Open beta keys. I got mine a few hours ago and I Still have no updated status on being verified for open beta. I did get the "Key already activated" error and dropped me to a screen to register a different key, and my account info is blank.
I am not going to worry about it now since you say its linked to my account.