[Speysider]

It's one of your custom codes that's stopping the page loading.

In your showthread template, find this code:

<!-- Digg --> 
<td class="vbmenu_control" id="digg" nowrap="nowrap"> 
<script type="text/javascript"> 
digg_url = 'http://www.skybluestalk.co.uk/showthread.php?t=6531';
digg_title = "New kit?";
digg_bgcolor = '#6EA2D7';
digg_skin = 'compact';
digg_window = 'new';
</script> 
<script src="http://digg.com/tools/diggthis.js" type="text/javascript"></script> 
</td> 
<!-- / Digg -->

And remove it. It's due to callbacks being made and being errored. Removing that code should make the page load again.