Error message

I recently installed tasklist and tasklist_advanced. Tasklist works fine, but when I install tasklist advanced, and click on mysite.com/tasks, I get the following error message.

user warning: Unknown column 't.parent' in 'field list' query: SELECT n.nid, t.parent, u.name AS assigned_name, t.assigned_to, a.taskcategory, a.tasktype, a.task_tree_left, a.task_tree_right, a.task_tree_depth, u.data FROM node n INNER JOIN tasks t ON t.nid = n.nid INNER JOIN tasks_advanced a ON a.nid = n.nid LEFT JOIN users u ON u.uid = t.assigned_to WHERE n.status = 1 AND n.type='tasks' ORDER BY u.name, a.task_tree_left ASC, IF(t.completed = 0, 0, 1), t.completed DESC in /home/mysite/public_html/includes/database.mysql.inc on line 172.

Any clues what is causing this?