The menu is not displaying because you heave not defined an image in the menu_ie.css file.
In the menu_ie.css file, change the background-image: none; property of the
ul#cssmw_home li span a selector to:
background-image: url(../../Images/btn_topNav.png);
as for the columns not displaying correctly in IE6, I cant spot the problem in the CSS, it's possible you have some conflicting styles. Perhaps the following article may prove useful:
css-column-tricks/