I tried your solution of clicking on the preview window. I get a page with none of the images present no matter the design type and no matter what color I select, everything appears the same. The only thing that changes is when I select the text which has to be a certain setting so it goes with the rest of the site. As I said, this is unacceptable and the extension is worthless to me. I would like a refund for the upgrade.
Also you mention having the supporting css and image files. The one template I sent you is a blank html document with no images, no css - only a single editable region. That locks up also. I would say this isn't related to those supporting files based on that.