IE bug

I follow this tutorial to make a menu for my website.
http://www.kirupa.com/css/css_rollovers.htm
However, the menu works perfectly in Firefox but in IE(6&7), the top menu (in vertical order) does not shows while the MOUSE still change. The second menu does not roll correctly, just move up a bit and the last 4 menu work fine, just like in Firefox.

Is there anyway to have this works in IE.
Thanks