When I enter my Team Sabre CD key on NovaWorld, it keeps telling me that the key is i
 

PROBLEM:
When I enter my Team Sabre CD key on NovaWorld, it keeps telling me that the key is invalid.

RESOLUTION:
If this is a new NovaWorld account, make sure you have entered a key for Delta Force – Black Hawk Down, before entering the key for the Team Sabre expansion. The page on which you enter the CD key will tell you exactly which key you should be entering. Make sure you read the directions on the page carefully.

some keep asking about this still till this day

i like to add one more to this

when you enter the keycode on the site only use low case keys and no --- in it at all

it would look something like this when you enter it

keycode is not real only sample: 9sf8dj3jw3830883h0h97hv9ha

then hit enter

you should be set