I an not sure what you mean by 'tiling', -didn't see this and didn't paste absolute paths to your images, but made some expected changes:
Corrected a spelling error, -"margin" where you had spelled it "maring" in the STYLE "body", created a style declaration of the ID "all" which in your html was there but absent in the STYLEs, fixed that navigation from moving around (mostly, made it relative instead of absoslute, so that anything AFTER it will not be display ON TOP of it...) and also changed it's width "100%" to the SAME WIDTH (in pixels) as the id "MAIN" so that it stays put when you re-size the browser viewport, -and a few other small changes too minor to recall.
Not sure where/how your background images will look now, but the code is more stable and should start to make sence.
Noted that you use geocities... it puts ads and things that crowd-out your content, mooshing things around. And possibly adding scripts of it's own... I suggest another AD-FREE, COST-FREE hosting site, like awardspace.com or sitesled.com, the former being my favorite for the 200GBs that they give you for free, their speed and up-time. :)
Your code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<link rel="stylesheet" href=
"http://themis.geocities.yahoo.com/jsoff.css?thIP=70.29.28.72&thTs=1147956549"
type="text/css">
<title>:about us</title>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<style type="text/css">
body
{background: #c9c9c9;
margin: 0; padding: 0;
text-align: center;
}
#nav
{position: relative; width:702px;/* <- This width MUST be same width as #main in order to work */
top: 3em; left: 3em;
}
#nav ul li
{margin: 0;
padding: 0;
list-style: none;
display:inline;
margin-right:85px;/*controls spacing of list-items*/
}
#main
{clear: both;
border:1px solid gray;
position:relative;
top:35px;
text-align: left;
margin:auto;
width: 702px;
padding: 0;
font-size: 14px;
}
#all {margin:auto;}/* a 'wrapper': this centers page on different width browser screens*/
p.text1
{
margin: 0;
width: 662px;
padding: 10px 20px;
line-height: 1.9em;
background: url(tilec.gif) 0 0 repeat-y;
}
h2
{
background: url(Images/about.jpg) 50% 0 no-repeat;
}
h2 span
{display: none;}
h3
{
background: url(topc.gif) 0 0 no-repeat;
height: 20px; width: 702px;
text-align: center;
font-weight: bold;
color: #485FAF;
margin: 0;
padding: 0;
padding-top: 6px;
}
#txtbottom
{
background: url(bottomc) 0 0 no-repeat;
height: 26px; width: 702px;
border:1px dotted red;
padding: 0; margin: 0;
}
a {color: #909092; text-decoration: none;}
</style>
</head>
<body>
<div id="all">
<div id="nav">
<ul>
<li><a href="home.html">home</a></li>
<li><a href="service.html">services</a></li>
<li><a href="affiliates.html">affiliates</a></li>
<li><a href="contact.html">contact us</a></li>
</ul>
</div><!-- closes NAV div -->
<div id="main">
<h3>Sewage-System.inc</h3>
<p class="text1">We are one of the worlds leading manufacturers of
large-scale, commercial sewer systems with projects around the
world. As a pioneer in the field of commercial, Controlled
Environment Sewage, it is highly likely that you the consumer have
selected quality produce off the shelves of your supplier, made by
us. Responding to repeated requests from consumers, we have decided
to add to our product-line a backyard variety pipe system that
would be efficient and easily affordable to average end-use
consumers. You can be confident in your sewage system with the name
tried and true name Sewage-System.inc behind you.</p>
<div id="txtbottom"><p class="text1">text bottom</p></div>
</div><!-- closes MAIN div -->
</div><!-- closes ALL div -->
</body>
</html>