Widget will not display

Hi,

I maintain several wordpress websites, and currently two of them display LibraryThing book cover widgets. Just recently I noticed that one of the sites cannot load the widget and the revolving loader displays continually. The other site is displaying the widget correctly.
I am not sure whether:/ the theme of the disfunctional site is blocking the widget. The theme for the site on which the widget is not working is the heavy photocrati framework.
or /there is a plug-in I am using on the framework that is causing the issue.
Both websites are the same version wordpress.
I can list the plug-ins installed on both sites if that would help anybody, but I am hoping that someone else has experienced this (recent) issue and can suggest a rapid solution.
Many thanks in adavance,

Foxsch