problem bei headernavi

<style type="text/css" media="screen">
<!--
body
{
font-family: Verdana, sans-serif;
font-size: 40px;
overflow: auto;
padding: 16px;
margin: 10px;
}

ul, li
{
list-style-type: none;
padding: 5px;
margin: 5px;
}

li a
{
padding-right: 10px;padding-top: 10px;
}

div.menu
{
position: absolute;
z-index: 3;
top: 143px;
left: 50%;
margin-left:-405px;
width:905px;
}

.menu li
{
width: 60px;
float: left;
}

.menu a
{
border: 0px solid #xxxxxx;
background-color: #xxxxxx;
background-image: url();
text-decoration: none;
text-align: center;
font-weight: bold;
cursor: pointer;
margin: 0px;
display: block;
height: 23px;
color: #ffffff;
}

.menu a:hover
{
background-color: #xxxxxx;
background-image: url();
text-decoration: underline;
}

#smenu1, #smenu2, #smenu3, #smenu4, #smenu5
{
font-size: 30px;
display: none;
width: 250px;
float: left;
}

#smenu1 a, #smenu2 a, #smenu3 a, #smenu4 a, #smenu5 a
{
font-weight: bold;
padding-top: 5px;
border-top: 0px;
cursor: pointer;
color: #FFFFFF;
}
//-->

</style>

<script type="text/javascript">
<!--
function montre(id)
{
with (document)
{
if (getElementById)
getElementById(id).style.display = 'block';
else if (all)
all[id].style.display = 'block';
else
layers[id].display = 'block';
}
}

function cache(id)
{
with (document)
{
if (getElementById)
getElementById(id).style.display = 'none';
else if (all)
all[id].style.display = 'none';
else
layers[id].display = 'none';
}
}
//-->
</script>
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</ul>
</li>
</div>