Hiya,
In your 'cssmw1/menu.css':
Remove the 'z-index: 100;' from your 'ul#cssmw1 li' style (about line 23):
ul#cssmw1 li {
background-image: none;
padding: 0 0 0 0;
position: relative;
white-space: nowrap;
}
and add it to your 'ul#cssmw1 ul.level-1' style (about line 77):
ul#cssmw1 ul.level-1 {
left: 132px;
margin-right: 25px;
z-index: 100;
}