Weird, the same thing happened to me. I think their site is having problems at the moment. I switched back to US, placed the order, and then got a UK error page, but also an email confirmation of the order.
The Gitmans really tempted me, but I just bought 2 from Acrimony's sale. I'm not really looking for anything else right now, and in an effort to institute some discipline, I've made a list of stuff I need, and if it's not on that list, I don't buy it.