There's little danger of running out of hotel rooms, because the Fairmont has more rooms than the convention has members, and we've been reassured that if we were to fill our initial block of rooms it should not be difficult to get more. But as the note I put on the hotel information page says, if you want to book right now, call the hotel directly at the number shown on the booking page and you can make the reservation that way (this is why we know the rooms are really available), but then e-mail the hotel liaison to say you've done so.
My participation in this is to update the WFC web site pages quickly. If you happened to be looking at the WFC web pages late yesterday afternoon, you would have seen the site pages changing every few minutes while I worked to rearrange things in what I hope is a logical manner.
When the booking site bug is squashed, we'll start making announcements in other places.
Update, 1455: Updated the nature of the error after some more experimenting with individual nights and isolating the problem.