A ver te dejo un codigo CSS que yo uso y me funciona sin problemas, alo mejor te sirve:
Código HTML:
/* Boxes */
#top {
margin: 0px 0px 0px 0px;
padding: 10px;
border: 0px;
background: #fff;
height: 165px; /* ie5win fudge begins */
voice-family: "\"}\"";
voice-family:inherit;
height: 145px;
width: 928px;
text-align: center;
}
html>body #top {
height: 145px; /* ie5win fudge ends */
}
#left {
position: absolute;
top: 165px;
left: 0px;
margin: 0px;
padding: 10px;
border: 0px;
background: transparent;
width: 230px; /* ie5win fudge begins */
voice-family: "\"}\"";
voice-family:inherit;
width: 210px;
}
html>body #left {
width: 210px; /* ie5win fudge ends */
}
#right {
position: absolute;
top: 165px;
left: 230px; /* Opera5.02 will show a space at right when there is no scroll bar */
margin: 0px;
padding: 10px;
border: 0px;
background: transparent;
width: auto;
width: 698px;
voice-family: "\"}\"";
voice-family:inherit;
}
/* End boxes */
Lo unico que tienes que hacer es acomodarlo a tus tamaños...
Enjoy. Salu2!