I go to the account, click on Use a Serial Code and enter it
Then why do i get this message:
You can't use the supplied serial code.
The supplied serial code is valid, but it can not be used to create a new account and it can not be applied to any accounts you already have.
The ability to acquire NCoin through the use of serial codes will be implemented by Monday Nov 28th just in time by Cyber-Monday. Until then, NCoin may still be purchased directly using a credit card or similar method.