That's because your /includes/templates/iC_AthemeV1.3/css/stylesheet_header_menu.css file contains a call to csshover.htc:
Code:
body {
behavior: url(csshover.htc);
}
Only IE needs csshover.htc because it's the only browser that isn't smart enough to do css hover effects on its own without the aid of helps.
And, attempting to access /shop/csshover.htc on your server fails ... as in the file isn't found.
Your simplest fix is to upload the csshover.htc file to your /shop/ folder so that IE can find it when it needs it.