I'm not sure if it will help at all, but I can see that you are missing the CSS attribute top for both #leftbg and #rightbg.
code:
#leftbg {
background-image: url('left-bg.jpg');
height: 100%;
width: 184px;
top: 0px;
left: 0px;
position: fixed;
}
#rightbg {
background-image: url('right-bg.jpg');
height: 100%;
width: 184px;
top: 0px;
right: 0px;
position: fixed;
}
EDIT:
oh wait, i didn't see the IE specific code listed. Still should be the same though. If you use postion: absolute anywhere, you always need one attribute from each of top/bottom and left/right