Neatlin Admin vs. Public site appearance problems

I've been running into two problems with Neatline.

First, none of the Stamen maps appear in the public when I am looking at the public Neatline exhibit, there is simply a blank white background. When looking in the Admin editing view the Stamen maps appear without difficulty though. Furthermore, all of the google maps load without problem.

Secondly, and conceivably related, I am running into the same trouble with WMS layers. I am serving up a number of geo-referenced old maps which load perfectly on the admin side, but do not appear when looking at the public site.

I'm fairly lost as to what is causing these problems.

Any advice is much appreciated.

Sincerely, Evan