I added the WPMU Dev Dashboard to this site today, and upgraded to the latest version of Appointments+ (I had previously upgraded to the beta version), and things appeared fine. Settings carried over, confirmed appointments, etc.
I'm now attempting to make a test appointment, but when I click a time slot, the little loading timer just sits and cycles. I never get to the next step.
The page is: http://newyousmilecenter.com/booking