strange behaviour in "simple" template

I attached a handful of photos to a page and when if I insert [gallery link="none" template="simple"] I get three columns of clickable thumbs on the right hand side, and on the left hand size is a roughly 300x25px grey rectangle. When I click a thumb, the rectangle shows a loading icon for a few seconds and then nothing.

http://ww.wp.xz.cn/extend/plugins/file-gallery/