Verzweifelt an komischen CSS Problem

<style type="text/css">



.markermenu{
list-style-type:none;
margin: 5px 0;
padding: 0;
width: 170px;

}

.markermenu li a{
background: white url(media/arrow-list.gif) no-repeat 2px center;
background-color: #c44d29;
font: bold 13px "Lucida Grande", "Trebuchet MS", Verdana, Helvetica, sans-serif;
color: #242a49;
display: block;
width: auto;
padding: 3px 0;
padding-left: 20px;
text-decoration: none;
border-bottom: 1px solid #B5B5B5;
}
.markermenu ul a{
color: #ffffff;
}


* html .markermenu li a{ /*IE only. Actual menu width minus left padding of LINK (20px) */
width: 150px;
}

.markermenu li a:visited, .markermenu li a:active{
color: #00014e;
}

.markermenu li a:hover{
color: black;
background-color: #ffffcb;

}

</style>

    <!-- Menü begin -->
      <div id="sidebar1" class="markermenu"><ul id="markermenu"><li class="active"><a href="http://xxxxxxx/" title="Home" >Home</a></li>
<li><a href="/xxx/index.php?id=2" title="Über uns" >Über uns</a></li>
<li><a href="/xxx/index.php?id=3" title="Aktuelles" >Aktuelles</a></li>
<li><a href="/xxx/index.php?id=4" title="Referenzen" >Referenzen</a></li>
<li><a href="/xxx/index.php?id=15" title="Ansprechpartner" >Ansprechpartner</a></li>
<li><a href="/xxx/index.php?id=16" title="Service" >Service</a></li>
<li><a href="/xxx/index.php?id=17" title="Impressum" >Impressum</a></li>
<li class="last"><a href="/xxx/index.php?id=18" title="Kontakt" >Kontakt</a></li>
</ul></div>
<!-- Menü end -->