I'm betting it's a redesign. I think I got an error message recently that said as much. It's been really quiet over there for months, so I guess they figured no one would notice. Of course, with winter just around the corner, people have noticed. Hopefully it will be back up soon.
Not to worry. Here is a copy of the email that I got a week or 2 ago from NASTAR HQ.
"Hello NASTAR Pacesetters & Coordinators,
You may have noticed that the NASTAR web site is currently unavailable. We are in the process of updating nastar.com so please use the following e-mail address to contact me or to return your NASTAR Materials order form (attached):