Hmmm - Well here is the coding I have for my DIV 
[code]#centeredmenu {
clear: both;
float: left;
margin: 0px;
padding: 30px;
border-bottom: 0px solid #000; /* black line below menu /
width: 100%;
font-family: Verdana, Geneva, sans-serif;
font-size: 120%;
z-index: 1000; / This makes the dropdown menus appear above the page content below */
position: relative;
top: -60px;
}
/* Top menu items /
#centeredmenu ul {
margin:0;
padding:0;
list-style:none;
float:right;
position:relative;
right:50%;
}
#centeredmenu ul li {
margin:0 0 0 1px;
padding:0;
float:left;
position:relative;
left:50%;
top:1px;
}
#centeredmenu ul li a {
display:block;
margin:0;
padding:.6em .5em .4em;
font-size:1em;
line-height:1em;
background:#FFF;
text-decoration:none;
color:#6ac25b;
font-weight:none;
border-bottom:0px solid #000;
}
#centeredmenu ul li.active a { / Main #2 /
color:#6ac25b;
background:#FFF;
}
#centeredmenu ul li a:hover {
background:#6ac25b; / Top menu items background colour /
color:#FFF;
border-bottom:0px solid #03f;
}
#centeredmenu ul li:hover a,
#centeredmenu ul li.hover a { / This line is required for IE 6 and below /
background:#6ac25b; / Top menu items background colour */
color:#FFF;
border-bottom:0px solid #03f;
}
/* Submenu items /
#centeredmenu ul ul {
display:none; / Sub menus are hiden by default */
position:absolute;
top:2em;
left:0;
right:auto; /*resets the right:50% on the parent ul /
width:10em; / width of the drop-down menus */
}
#centeredmenu ul ul li {
left:auto; /*resets the left:50% on the parent li /
margin:0; / Reset the 1px margin from the top menu /
clear:left;
width:100%;
}
#centeredmenu ul ul li a,
#centeredmenu ul li.active li a,
#centeredmenu ul li:hover ul li a,
#centeredmenu ul li.hover ul li a { / This line is required for IE 6 and below /
font-size:.8em;
font-weight:normal; / resets the bold set for the top level menu items /
background:#FFF;
color:#000;
line-height:1.4em; / overwrite line-height value from top menu /
border-bottom:1px solid #DDD; / sub menu item horizontal lines /
border-top:1px solid #DDD;
border-left:1px solid #DDD;
border-right:1px solid #DDD;
}
#centeredmenu ul ul li a:hover,
#centeredmenu ul li.active ul li a:hover,
#centeredmenu ul li:hover ul li a:hover,
#centeredmenu ul li.hover ul li a:hover { / This line is required for IE 6 and below /
background:#6ac25b; / Sub menu items background colour */
color:#FFF;
}
/* Flip the last submenu so it stays within the page /
#centeredmenu ul ul.last {
left:auto; / reset left:0; value /
right:0; / Set right value instead */
}
/* Make the sub menus appear on hover /
#centeredmenu ul li:hover ul,
#centeredmenu ul li.hover ul { / This line is required for IE 6 and below /
display:block; / Show the sub menus */
}
[/code]
How does that look?