You don't have permission to access /forums/admin.php on this server.
I've moved host and installed LAMP myself. Can't say I've ever run into this problem myself.
Error logs show
[Fri Feb 15 16:19:16 2013] [error] [client 18.104.22.168] client denied by server configuration: /var/www/sociallyuncensored.eu/public_html/forums/admin.php
Any help would be helpful.