Hi Stephen1912,
I'd like to clarify what was meant with registered user. I suspect you understand this to mean that you have activated your game and the NH addon with your license keys perhaps.
But what was meant was registering your license keys in your forum profile too. When you register your SS08 license key on the forum, you will have access to the entire forum, including the missions boards. On there, you can find fixes for some missions already, that you might now miss. As far as I know, there have been fixed versions released that should render all your troubled missions playable again.
And, as a bonus, you can also download a free addon vessel from your forum profile after you're registered. The 'Jumbo Javelin'. Which is a great vessel, so don't miss out!
If you go to your forum profile and scroll down a bit, you will come across the license key registration box. Only the SS08 key is needed to get full acccess to the SS08 boards and the bonus vessel, but it can't hurt to register all the keys you might have, if only for safekeeping alone. Once you're registered, then you'll find the download link to the bonus vessel in there as well, a bit further down.
Hopefully that clears it up a bit.
Kind regards,
Fred