Hello,

Can you try to execute these SQL queries and see how it goes:

ALTER TABLE `jos_discuss_posts` ADD COLUMN `cluster_id` INT(11) NOT NULL default 0;
ALTER TABLE `jos_discuss_posts` ADD COLUMN `cluster_type` VARCHAR(255) NULL;
ALTER TABLE `jos_discuss_thread` ADD COLUMN `cluster_id` INT(11) NOT NULL default 0;
ALTER TABLE `jos_discuss_thread` ADD COLUMN `cluster_type` VARCHAR(255) NULL;

May I know which version are you updating from? If this doesn't help, can you provide us your phpmyadmin access so that we can take a look on your database tables.