why can't I get lightbox to work with a fadeIn?!

why can't I get lightbox to work with a fadeIn?!

I've read a few forums about people who had trouble but none of them helped...

the head looks like this:
<script src="js/cufon-yui.js" type="text/javascript"></script>
<script src="js/Nudista_light.js" type="text/javascript"></script>
<script type="text/javascript" src="js/prototype.js"></script>
<script type="text/javascript" src="js/scriptaculous.js"></script>
<script type="text/javascript" src="js/lightbox.js"></script>
<script src="js/jquery.js" type="text/javascript"></script>

<script type="text/javascript">
$(document).ready(function(){
  $(".header em").click(function () {
              $("#portfolio").fadeIn("slow");
            });  });
           
    Cufon.replace('h1, a',  { hover: true });
</script>
<link rel="stylesheet" href="css/lightbox.css" type="text/css" media="screen" />


* all properly linked

an example of the body looks like this:
        <a href="images/markville01.jpg" rel="lightbox[mark]" title="Cadillac Fairview - Transforming markville shopping centre"><img src="images/markville_thumb.jpg" width="205" height="135"/></a>
        <a href="images/markville02.jpg" rel="lightbox[mark]" title="Markville Presentation Folder"></a>
        <a href="images/markville03.jpg" rel="lightbox[mark]" title="Information materials"></a>
        <a href="images/markville04.jpg" rel="lightbox[mark]" title="Construction Sinage"></a>
        <a href="images/markville05.jpg" rel="lightbox[mark]" title="Signage"></a>
        <a href="images/markville06.jpg" rel="lightbox[mark]" title="Website: transformingmarkville.ca"></a>

when I click on the img it just opens in a new window and doesn't lightbox...when I used firebug I got this error:

element.dispatchEvent is not a function - on the prototype.js

Now...I was reading about some NoConflict thing to solve this but when I add it in it doesn't work I end up getting some error like ".header em" is null so I take out that fadein script but kept the NoConflict then the lightbox worked, but I need that fade in to work too.

At the moment the site isn't live so I can't show you guys exactly but I'll describe what I'm trying to accomplish. There is a block of text in the header and I targeted the "em" so when it is clicked a thumbnail fades in and when you can lightbox it when clicked...

I think the fadeIn is what's screwing everything up cause when I take it out it works fine...