Problema con posicionamiento absoluto en DW CS2

[ViruSam]

y aqui la hoja de estilos CSS:

body {
background-color: #000000;
text-align: center;
margin: 0px;
padding: 0px;
}
.contenedor {
font-family: "Lucida Console";
background-color: #000000;
margin-right: auto;
margin-left: auto;
height: 600px;
width: 1000px;
border: 1px solid #FFFFFF;
margin-top: 150px;
margin-bottom: 150px;
font-size: 12px;
color: #FFFFFF;
}
.principal {
margin: 0px;
padding: 0px;
float: right;
height: 520px;
width: 845px;
border: 1px solid #FF0000;
}

.encabezado {
background-color: #000000;
height: 40px;
border-top-width: 1px;
border-right-width: 1px;
border-bottom-width: 1px;
border-left-width: 1px;
border-bottom-style: solid;
border-top-color: #FFFFFF;
border-right-color: #FFFFFF;
border-bottom-color: #FFFFFF;
border-left-color: #FFFFFF;
text-decoration: none;
}
.fuente2 {
font-family: "Lucida Console";
font-size: 12px;
color: #999999;
text-decoration: none;
text-align: right;
}

.div-menu {
font-family: "Lucida Console";
font-size: 12px;
line-height: 20px;
color: #FFFFFF;
background-color: #000000;
text-align: center;
padding: 1px;
width: 115px;
float: left;
border-top-width: 1px;
border-right-width: 1px;
border-bottom-width: 1px;
border-left-width: 1px;
border-right-style: solid;
border-top-color: #FFFFFF;
border-right-color: #FFFFFF;
border-bottom-color: #FFFFFF;
border-left-color: #FFFFFF;
}
.submenu {
margin: 0px;
padding: 0px;
width: 150px;
border: 1px solid #FF0000;
float: left;
}
.celda-submenu {
width: 145px;
padding: 0px;
height: 80px;
border: 1px solid #FFFFFF;
text-align: left;
margin-top: 2px;
}
.pi1 {
background-image: url(pi2.gif);
height: 80px;
width: 145px;
position: absolute;
visibility: hidden;
}


a:link {
font-family: "Lucida Console";
font-size: 10px;
color: #FFFFFF;
text-decoration: none;
background-color: #000000;
}
.menu-navegador {
background-color: #000000;
text-align: left;
margin: 0px;
padding: 5px;
height: 20px;
float: left;
}
.Fuente1 {
font-family: "Lucida Console";
font-size: 16px;
color: #999999;
background-color: #000000;
text-align: left;
line-height: 40px;
}
.pi2 {

background-image: url(pi2.gif);
height: 80px;
width: 145px;
position: absolute;
visibility: hidden;
}
.pi3 {
background-image: url(pi2.gif);
height: 80px;
width: 145px;
position: absolute;
visibility: hidden;
}