Lightbox's shadow shows only partly

[ami]

1) Script Title: Lightbox Image Viewer

2) Script URL (on DD): http://www.dynamicdrive.com/dynamici...tbox/index.htm

3) Describe problem: Problem when using IE. The script works perfectly here on DD, but when I use it on my own website, the shadow behind the picture shows only on top of the page, not on the whole page. When I scroll the page down, the shadow ends. I was just wondering if there are anything (some elements?) that makes it go wrong, or is it just that my site/host doesn't let the script work perfectly on IE.

[ami]

... so there's nothing that can be done?