[Diesel,]

define('DISABLE_HOOKS', true);

Add this to your config.php file located in your includes folder of your forum root directory, This will disable plugins without needing access to your admin cp, Once you have added this and uploaded your forums should load fine. From here you can just uninstall the plugin.

Incase you don't know where to add it here's an example.

<?php
define('DISABLE_HOOKS', true);

Hope this helped.

Regards,
Diesel