Clicking thumbnails causes issue

So far, the plugin is working great. However, when I click on a thumbnail, it initially does as expected – a lightbox window opens with the larger image. After about a second, the lightbox image disappears and the page forwards to a 404 page (see attached image and url). Any suggestions for fixing this?

Thanks!
http://www.the-foundery.com

[ screenshot ]

http://ww.wp.xz.cn/extend/plugins/simply-instagram/