First off, the site in question is http://188.8.131.52
If you open the site in Internet Explorer (6 or 7) and try to use the navigation system, the popup submenu is not visible. The main content of the site is overlapping it. It works fine in most other browsers.
I have already tried searching this forum for similar issues but to no avail.
Any help would be much appreciated.
Got the problem fixed - we had to adjust the z-index of the divs that encompassed the unordered list.