It might have to do with B&N's servers. I know that there seems to be a lot of issues lately.
People are not being able to connect to the ship, and so forth.
Try again in a few hours.
The other possibility is that your network is connecting but there is something else going wrong. What type of router do you have? What type of encryption etc?
Just keep hitting continue and try to reconnect and it will eventually. It was a bug with the shipping OS - as soon as you connect to WiFi it will download and update itself and it won't happen again.
I tried several times and got the same thing. All I did was unplug the router, waited a minute or 2 and the next thing I knew everything was as it should be and my new nook hd was registered. hopefully this, as simple as it is, will work for you or anyone else for that matter. IF the issue has not been resolved already,