Hi im trying to instert flash as my header using css but it wont work it puts it in totally wrong place

Code:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/css; charset=iso-8859-1">
<title>Bjrautosalvage</title>
<style type="text/css">

#container {
width:780px;
margin: 10px auto;
background-color:#fff;
color:#333;
border:1px solid gray;
line-height:130%;
}
#header {
padding: .5em;
height:90px;
}
#mainnav {
float:none;
width:100%;
margin:0px;
padding:0;
background-image:url(navbar bg.jpg);
background-repeat:repeat;
}
#mainnav h5{
padding: 0;
margin: 0;
}
#content {background-color:#FFFFFF;
}
#menu {
float:right;
width:160px;
margin:0px;
padding:1em;
border-left: 1px dashed black;
}

a.link:hover {
	color:#000000;
	background-color:inherit;
	text-decoration:none;
	padding:0 3px 0 3px;
	border-bottom:#000000 1px solid;
	}
	.link, a.link:link, a.link:visited, a.link:active {
	text-align:center;
	color:#000000;
	background-color:inherit;
	font-size:h5;
	padding:0;
	text-decoration:none;
	}
	
	


.style1 {font-size: 12px}
.style1 {font-size: 14px}
.style2 {
	color: #000000;
	font-family: Arial, Helvetica, sans-serif;
}
.style3 {font-family: Arial, Helvetica, sans-serif}
.style4 {
	font-size: 18px;
	font-family: Arial, Helvetica, sans-serif;
}
.style5 {font-size: 18}
.style9 {color: #FFFFFF}
</style>
</head>

<body>

<div id="container"></div>
<div id="header"><object width="398" height="156">
<param name="movie" value="header.swf">
<embed src="header.swf" width="398" height="156">
</embed>
</object></div>
<div id="mainnav">   
  <div align="left" class="style1">
    <h5 class="style2">&nbsp;</h5>
  </div>
</div>
<div id="content">
</div>

</div>
</body>
</html>
What have i done wrong??