I think I am going insane!!!!

This code seems so simple but I can not get it to work. I am trying to preload images for use in an image swap. This is the code I am using

<body onLoad="preloadimages('ro_bui.jpg', 'ro_mar.jpg', 'ro_sto.jpg', 'ro_mec.jpg', 'ro_pai.jpg', 'ro_fib.jpg')">

<script language="JavaScript" type="text/javascript">
<!--
function preloadimages() {
var roimages=new Array();
var arguments=preloadimages.arguments;
for (i=0;i<arguments.length;i++){
roimages[i]=new Image();
roimages[i].src=preloadimages.arguments[i];
}
}
-->
</script>

In the mouseover event I have

<a href="marina.htm" onmouseover="document.images['ro'].src=roimage[0].src" onmouseout="document.images['ro'].src='ro_base.jpg'">

for each rollover.

Can anybody tell me what I am doing wrong?!?!?!

I am viewing the page on ie6