in the admin.css, remove overflow hidden from the body:
body {
background-color: #004899;
color: #2c2d2e;
font-family:Arial, Helvetica, sans-serif;
font-size: 11px;
margin: 0 0 0 0;
padding: 0 0 0 0;
text-align: center;
background-image: url(../images/body_bg.png);
background-repeat: repeat-x;overflow: hidden;
}
i don't think margin top is needed for the pages div
<div class="pages" style="float:left; width:220px; clear:left;margin-top:0;">
add overflow hidden to the #outerWrapper #contentWrapper #content
#outerWrapper #contentWrapper #content {
background-color: #fff;
margin: 0 0 0 240px;
padding:0 10px 0 0;
}