i have the following simple script, but it doesn't work in IE7

<div id="content">
    <div id="left"></div>
    <div id="right"></div>
    <div id="bottom_menus">any text here...</div>
</div>

and CSS

#content
{
    margin: 0 auto;
    padding: 0;
    width: 980px;
    background-color: lime;
    height: 800px;
    overflow: hidden;
    position: relative;
}
#left
{
    width: 275px;
    float: left;
    background-color: olive;
    margin: 0px 0px -5000px 0;
    padding: 0 0 5000px 0;
    min-height: 400px;
}
#right
{
    width: 704px;
    float: left;
    background-color: red;
    margin: 0px 0px -5000px 0;
    padding: 0 0 5000px 0;
    min-height: 400px;
}
#bottom_menus
{
    background-color: orange;
    height: 15px;
    position: absolute;
    bottom: 0px;
    width: 100%;
}

why position absolute doesn't work? thanks in advance