ho risolto in sostanza il problema, rendendo la pagina compatibile sia con IE6 sia con FireFox, in questo modo:

codice:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html dir="ltr" lang="it">
  <head>
    <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1" />
    <style TYPE="text/css">
body
{
background-color: #EDF2FC;
background-image: url(imgmv1/nuv2.jpg);
scrollbar-face-color: #C8D6FB;
scrollbar-highlight-color: #303030;
scrollbar-shadow-color: #484848;
scrollbar-arrow-color: #000000;
scrollbar-track-color: #000000;
}
.dista
{
margin: 0px 0px 0px 0px;
}
td
{
border-style: solid;
padding: 0;
border-color: #8BA9E5;
border-right-width: 1px;
border-top-width: 1px;
border-left-width: 1px;
border-bottom-width: 1px;
}
.argome
{
background-color: #EDF2FC;
border-color: #5582D2;
border-right-width: 1px;
border-top-width: 1px;
border-left-width: 1px;
border-bottom-width: 1px;
padding: 0;
}
.attivo
{
background-color: #FFFFFF;
}
a:hover
{
background-color: #FFFFFF;
}
    </style>
tuttavia ho un problema nel far funzionare una istruzione in javascript:
window.status='stosito'