Image preload script problem...HELP!

[by350]

Can someone please tell me what's wrong with this preload script? The rollovers work fine, but I can tell that the images are not getting preloaded. Here is the code:

<!-- START PRELOAD SCRIPT -->
<script type="text/javascript" language="JavaScript">
<!--

function newImage(arg) {
if (document.images) {
rslt = new Image();
rslt.src = arg;
return rslt;
}
}

function changeImages() {
if (document.images && (preloadFlag == true)) {
for (var i=0; i<changeImages.arguments.length; i+=2) {
document[changeImages.arguments[i]].src = changeImages.arguments[i+1];
}
}
}

var preloadFlag = false;
function preloadImages() {
if (document.images) {
by_leftnav_resume_on = newImage("images/by_leftnav_resume_on_146x18.gif");
by_leftnav_portfolio_on = newImage("images/by_leftnav_portfolio_on_146x18.gif");
by_leftnav_latestwork_on = newImage("images/by_leftnav_latestwork_on_146x18.gif");
by_leftnav_contact_on = newImage("images/by_leftnav_contact_on_146x18.gif");
by_leftnav_personal_on = newImage("images/by_leftnav_personal_on_146x18.gif");
preloadFlag = true;
}
}

// -->
</SCRIPT>
<!-- END PRELOAD SCRIPT -->

AND HERE IS THE CODE FOR THE ROLLOVERS:

<!-- BEGIN LEFT NAV CONTENT -->
<a href="resume.html" onmouseover="changeImages('by_leftnav_resume', 'images/by_leftnav_resume_on_146x18.gif'); return true;" onmouseout="changeImages('by_leftnav_resume', 'images/by_leftnav_resume_off_146x18.gif'); return true;"><img name="by_leftnav_resume" src="images/by_leftnav_resume_off_146x18.gif" width="146" height="18" border="0"></a><br>
<a href="portfolio/index.html" onmouseover="changeImages('by_leftnav_portfolio', 'images/by_leftnav_portfolio_on_146x18.gif'); return true;" onmouseout="changeImages('by_leftnav_portfolio', 'images/by_leftnav_portfolio_off_146x18.gif'); return true;"><img name="by_leftnav_portfolio" src="images/by_leftnav_portfolio_off_146x18.gif" width="146" height="18" border="0"></a><br>
<a href="latestwork.html" onmouseover="changeImages('by_leftnav_latestwork', 'images/by_leftnav_latestwork_on_146x18.gif'); return true;" onmouseout="changeImages('by_leftnav_latestwork', 'images/by_leftnav_latestwork_off_146x18.gif'); return true;"><img name="by_leftnav_latestwork" src="images/by_leftnav_latestwork_off_146x18.gif" width="146" height="18" border="0"></a><br>
<a href="contact.html" onmouseover="changeImages('by_leftnav_contact', 'images/by_leftnav_contact_on_146x18.gif'); return true;" onmouseout="changeImages('by_leftnav_contact', 'images/by_leftnav_contact_off_146x18.gif'); return true;"><img name="by_leftnav_contact" src="images/by_leftnav_contact_off_146x18.gif" width="146" height="18" border="0"></a><br>
<a href="personal/index.html" onmouseover="changeImages('by_leftnav_personal', 'images/by_leftnav_personal_on_146x18.gif'); return true;" onmouseout="changeImages('by_leftnav_personal', 'images/by_leftnav_personal_off_146x18.gif'); return true;"><img name="by_leftnav_personal" src="images/by_leftnav_personal_off_146x18.gif" width="146" height="18" border="0"></a><br>
<!-- END LEFT NAV CONTENT -->

I ALSO HAVE onload="preloadImages();" in the BODY tag.

HELP HELP HELP!