iframe background - IE vs FF & NS

[liunx]

Given the following ...
/* EXTERNAL STYLESHEET */


#MainText {
position: relative;
margin-left : auto;
margin-right : auto;
top : 60px;
font-family : "Arial";
color : #001d75;
font-size :10px;
width : 680px;
height : 420px;
background-image : url(JSO_bg2.jpg);
}
... and <div id="MainText">

<iframe id="VariableText" src=http://www.webdeveloper.com/forum/archive/index.php/"JSO_pg_1.htm", width="680px" height="420px" />

</div>

the background image (JSO_bg2.jpg) shows up under both Firefox and Netscape 7, but IE loads the frame with a white background. Any thoughts?