Validating css; It’s all mumbo-jumbo to me

Can anyone perhaps explain to me why my page isn’t validating? The w3 website doesn’t really explain in a way that’s understandable to me what is wron with certain elements. Please take a look if you would.
It mentions certain tags being open and not allowed etc. When I open the file in internet explorer it looks the way it should but in netscape it looks weird.

Here is the web address…
[URL=http://www.graphic-ills.com]Graphic Ills[/URL]

Here is the css script:

body { background-color: #FCFAFA; margin-top: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px;

}
h1 { font-size: 2em; font-family: arial; }
p { font-size: 1.25em; text-align: left; margin-left: 2px; margin-bottom: 5px; }
ul { list-style-type: circle; font-size: 1.25em; text-align: left; margin-left: 25px; }

<!–

DIV.Slice-01 {
position: absolute;
background: #991225;
left: 0px;
top: 0px;
width: 200px;
height: 130px;
}

DIV.Slice-02 {
position: absolute;
background: #991225;
left: 260px;
top: 0px;
width: 480px;
height: 130px;
}

DIV.Slice-03 {
position: absolute;
background: #e1e3e1;
left: 0px;
top: 130px;
width: 740px;
height: 88px;
}

DIV.Slice-04 {
position:absolute;
left: 0px;
top: 240px;
width: 147px;
height: 47px;
}

DIV.Slice-05 {
position: absolute;
left: 147px;
top: 219px;
width: 3px;
height: 801px;
}

DIV.Slice-06 {
position: absolute;
background: #e1e3e1;
margin: 80px;
left: 120px;
top: 195px;
width: 540px;
height: 801px;
text-align: right;
color: #991225;

}

DIV.Slice-08 {
position:absolute;
left: 10px;
top: 298px;
width: 147px;
height: 47px;
}

DIV.Slice-09 {
position: absolute;
left: 10px;
top: 346px;
width: 147px;
height: 48px;
}

DIV.Slice-10 {
position: absolute;
left: 10px;
top: 394px;
width: 147px;
height: 48px;
}

DIV.Slice-11 {
position: absolute;
left: 10px;
top: 441px;
width: 147px;
height: 48px;
}

DIV.Slice-12 {
position: absolute;
background: transparent;
left: 0px;
top: 520px;
width: 147px;
height: 559px;
}

–>

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