in the menu.css file, change:
ul#cssmw li {
background-image: none;
float: left;
padding: 0 0 0 0;
position: relative;
white-space: nowrap;
z-index: 100;
}
to:
ul#cssmw li {
background-image: none;
float: left;
padding: 0 0 0 0;
position: relative;
white-space: nowrap;
z-index: 1;
}