[kh99]

I'm not sure if this will make any difference, but maybe try putting this in headinclude:

<vb:if condition="THIS_SCRIPT == 'showthread'">
<link href="http://myforum.com/prettify/src/prettify.css" type="text/css" rel="stylesheet" />
<script type="text/javascript" src="http://myforum.com/prettify/src/prettify.js"></script>

<script type="text/javascript">
        var theonload = window.onload;
        window.onload = function(){
            theonload();
            prettyPrint();
        }
</script>
</vb:if>

Then just make the bbcode:

<pre class="prettyprint">
{param}
</pre>

That has the disadvantage of always loading the prettyprint stuff whether or not it's used, but this way it's only loaded once.

If that doesn't work, if you could post a link to your threads that might help in figuring out (although I suppose you would have done that if you didn't want to keep it private).