Small problem with ThickBox script

For anyone who doesn't know, the ThickBox script can be found here: http://jquery.com/demo/thickbox/

I have it working... sort of. If you go to this page: http://www.reachingintoheaven.com/gallery.php?detail=5 you'll see that when you click the image, the "blackout part" (the transparent "shade" that is put over the site) only covers my header, not my whole page. I can't figure out why.

A little while ago this was working in IE, but not in firefox. Now it seems its not working in either. You should be able to get at any code you need by viewing the source, but let me know if you want me to post a portion of it for you to review.

Can anyone help?

Thanks in advance.