some javascript problems with IE

hello, i have a problem with some java functions and IE. When i try to open same page with IE images will not load. With all other browsers this code will work properly. I have posted the code here, and the link to this is: http://www.netplague.eu/projects/x/ . I simply don`t know why this is not working on IE, what seems to be the problem? Many thanks in advance.

<script language="JavaScript">

if (document.images){

orsq= new Image(280,130);
orsq.src="img/orsq.jpg";  

redsq= new Image(280,130);
redsq.src="img/redsq.jpg";
}

function changeImagewebdev()
{
document.images["jsbuttonwebdev"].src = "img/webdevor_small.jpg";
return true;
}
function changeImageBackwebdev()
{
document.images["jsbuttonwebdev"].src = "img/webdevred_small.jpg";
return true;
}
function changeImagewindev()
{
document.images["jsbuttonwindev"].src= "img/windevor_small.jpg";
return true;
}
function changeImageBackwindev()
{
document.images["jsbuttonwindev"].src = "img/windevred_small.jpg";
return true;
}
//bigimage
function changeImagewebdevbig()
{
document.images["jsbuttonwebdevbig"].src= "img/webdev_big.jpg";
return true;
}
function changeImageBackwebdevbig()
{
document.images["jsbuttonwebdevbig"].src = "img/main_orange.jpg";
return true;
}
//bigimagewin
function changeImagewindevbig()
{
document.images["jsbuttonwebdevbig"].src= "img/windev_big.jpg";
return true;
}
function changeImageBackwindevbig()
{
document.images["jsbuttonwebdevbig"].src = "img/main_orange.jpg";
return true;
}
function xwebdev(){
changeImagewebdev();
changeImagewebdevbig();
}
function ywebdev(){
changeImageBackwebdev();
changeImageBackwebdevbig();
}
function xwindev(){
changeImagewindev();
changeImagewindevbig();
}
function ywindev(){
changeImageBackwindev();
changeImageBackwindevbig();
}
</SCRIPT> 

<div class="img_pop">
<A href="#" onMouseOver="return xwebdev()" onMouseOut= "return ywebdev()" style="cursor:default"><img
name="jsbuttonwebdev" src="img/webdevred_small.jpg" width="280" height="130" border="0"
alt="web design"></A>
</div>

<div class="img_pop">
<A href="x" onMouseOver="return xwindev()" onMouseOut= "return ywindev()" style="cursor:default"><img
name="jsbuttonwindev" src="img/windevred_small.jpg" width="280" height="130" border="0"
alt="windows software" style="margin-top:20px"></A> 
</div>

<div style="float:left; width:600px; margin-top:40px; margin-left:40px;">
<A href="#"><img name="jsbuttonwebdevbig" src="img/main_orange.jpg" width="600" height="280" border="0" alt="web design" style="cursor:default"></A> 
</div>