[feldon23]

My first guess is that the extremely intrusive javascript popups added by CurvedSpaces.com are killing the script.

I can't even visit
http://wendy.curvedspaces.com/forum/ircbrowse.php
without a popup being added.

Also, when I visit
http://wendy.curvedspaces.com/forum/...62&action=read

I am seeing a Parse error on line 46, which in my copy is:
$php_self = $_SERVER['PHP_SELF'];

If your PHP is very old, maybe you need to use
$php_self = $HTTP_SERVER_VARS['PHP_SELF'];

but I would think the script would have failed on:
$action = $_GET['action'];
earlier in the script.