Scroll bar issues (IE vs Firefox)

So i have a div, which has CSS absolute position properties set so it’s 5% left, 5% right, 5% bottom, 50% top and auto height and width with scroll:auto property.
On Firefox this all functions normally… the text inside the div can be scrolled and the size of the div doesnt exceed the screen size.
On IE however, the scroll-bar doesnt appear at all… all it does is simply resize the div so you have to scroll the whole page, not just the div.
Any idea how to fix that?

Code for the div:

#tekst{
position:absolute;
top:50%;
left:5%;
width:auto;
height:auto;
right:5%;
bottom:5%;
background-image:url(images/menu_ozadje3.png);
background-repeat:repeat;
overflow:auto;
border-color:#000000;
border-width:thin;
border-style:solid;
padding:15px;
}