Help, please! Unable to change NY appt.

I need to change my student visa appointment at the NY consulate (because my DN hasn't yet written the letter he offered to do last week), but the site isn't responding.  Does anyone have any ideas?  I've read Shala's post on how to do so, but nothing at all happens. 

Edited to include:

You have to use Netscape or Microsoft browsers on the britainusa.com site.  Safari doesn't work.

Once I switched to Netscape, I followed Shala's directions, and I'm all set for Thursday, August 25.  I know they get testy if you go for your visa the day before you leave, but I tried hard to get there on the 17th.  Thanks anyway!