I'm setting up an ecommerce site for a friend and I just installed 3.6.1 on a new clean install of WP and I seem to be having the same issue. I get a blank page. If I try to preview the theme I get a server error notice. I have earlier versions of Atahualpa running on other sites on the same server just fine. How do I get an earlier version? I assume if I get an earlier version, I'd have to manually install? If so, were can I find info on doing that. Or, how soon do you expect to get the issue fixed on 3.6.1?

Any feedback you can give me will be greatly appreciated.

Never mind. I found 3.5.1 and got it installed and activated. My only question left is when will 3.6.X be fixed?

BTW - Atahualpa is a GREAT theme. I wouldn't consider using anything else on WP sites.

Take a look at this thread.