I am working on a site that has a repeating background image for the body and a couple of other background images for the nav bar and the footer.

The main background image shows up fine but the nav bar background image only shows in Firefox and Safari on a Mac but does not show up in IE 6 or 7.

I am positive this is extremely elementary, but I could use a little nudge here.

You can see the work in progress page here.

Thanks in advance for the help.