Getting a white page of nothing when trying to edit in Upfront

So I installed the ecommerce plugin, added some products and everything seemed to be working great. I edited the background and a few other things in Upfront on the products page and that worked great as well.

Now, however, every time I click Upfront to edit something on the Product page, I just get a white background and nothing happens (though the Cart tab at the top still shows and functions). The Upfront toolbar is on the left still, but only white on the right (and when I right click, it's not the Upfront menu, but the regular Chrome menu).

Any idea what's going on? I'd mentioned this problem in a previous question and I was asked to enable staff support and make a new question, so I have done so.

The specific url I'm having trouble editing is http://www.fixcoffee.net/store/products/

I don't seem to have any problems with any other pages. Thank you for any assistance.