Hello Exodus,
The keys that you have registered in your profile seem perfectly in order.
If you have installed both SS08 and NH at the same time, then there might be a chance that the keys need to be registered in another order. It might ask for the NH key first, whilst you might expect the main game key to be asked for first.
Could you make sure that you are entering the right one at the right moment?
If this doesn't help, let us know!
Regards,
Fred