Double vision

Using gallery link to image file: When any image is clicked first, the plugin fires 2 instaces of itself (you may see that there are two backgrounds layers because its darker and two images one on top of the other with a 10px vertical diference). if you click the next button this double vision stops, and from this point on all items appear normally (one instance each).

The page I need help with: [log in to see the link]