Forum credentials doesn't match "giveaway" credentials?

[CuriousMike]

I've tried to enter the "20th anniversary" giveaway - the login dialog pops up and I use my forum credentials.
They are refused.

As a test, I went to the forums, logged out, logged in (clearing both user/pw fields to ensure i'm typing them) and was ok.

As a further test, I changed my password from the forums.

I went back to the "Anniversary give-away" page, and tried to login with the updated credentials.
No go.
So, I tried the "reset password" option - which took me to a page that claims it doesn't know my email address.

There is a disconnect for me here.

 

[CuriousMike]

As an additional step, assuming perhaps the "give away" login credentials are different, I attempted to create a new account.
It claimed my username was already taken.

And... if they're separate credentials, maybe that's true?

 

[Crono]

They are indeed separate.