First, let me say, great plugin! I've been using it on a few different sites and have been thrilled with it thus far.
For some reason, my documents recently stopped displaying. They had been working just fine, but now I only see a black rectangle with no content. I'm experiencing this on two different WP installs on two different servers. It doesn't work in either Firefox, or Chrome... and I've tried it on both OSX and Win 7. It does (ironically) work in IE8.
The two sites are http://www.evolutionarycollective.com/category/content/articles/
I've tried running the plugin in the non-enhanced version, and I've tried adding
force=1 to the shortcode.