Position:absolute solucionado

@charset "utf-8";
/* CSS Document */
 
html, body {
	width:100%;
   height: 100%;
   overflow: hidden;
}
#container {
   top:0px;
   height: 100%;
   overflow: auto;
   position: relative;
   z-index: 1;
   background-color:#FFFFCC;
}
#div1 {
   position: absolute;
   top:20%;
   width:20%;
   height:60%;
   z-index: 2;
   background-color:#FFFF99;
}
#div5 {
   position: absolute;
   top:20%;
   width:60%;
   height:60%;
   z-index: 2;
   left:20%;
   background-color:#FF99CC;
}
#div2 {
	top:0.5%;
   position: absolute;
   width:100%;
   height:20%;
   z-index: 3;
   background-color:#CC3300;
}
#div3 {
   position: absolute;
   height:60%;
   width:20%;
   top:20%;
   left:80%;
   z-index: 2;
   background-color:#FFFF99;
}
#div4 {
	position: absolute;
	top:80%;
	width:100%;
	height:20%;
	z-index: 2;
   	background-color:#FFFF00;
}

 
        <title>Position:absolute en IE6 y Firefox</title>
 
 
 
 
    <div>
 
    </div>
<div>div id=div1</div>
<div>div id=div2</div>
<div>div id=div3</div>
<div>div id=div4</div>
<div>div id=div5</div>