MySQL Error

SCRIPT:
Number of MySQL function calls: 5
SQL statement:
SELECT node1.name , node1.id as id, COUNT(*) AS level, node1.description AS description, node1.public as public, node1.lastauthorname as lastauthor, node1.rgt AS rz, node1.lft AS lz, node1.sortorder, node1.gruppe, node1.msgcount, fu.userid, (SELECT m.creationdate FROM forums_threads t INNER JOIN forums_messages m ON m.threadid = t.id WHERE t.forumid = node1.id ORDER BY m.creationdate DESC LIMIT 1) as lastchanged FROM forums AS node1 INNER JOIN forums AS node2 LEFT JOIN forums_to_users fu ON (node1.id = fu.forumid) WHERE node1.rootid = 1 AND node2.rootid = 1 AND node1.lft BETWEEN node2.lft AND node2.rgt AND (node1.public = 1) GROUP BY node1.LFT ORDER BY node1.gruppe, node1.sortorder ASC, name ASC

MySQL error message: Unknown column 'node1.sortorder' in 'field list'

Kernel-Stack:

#FileLineCallArguments
1.   index.php4   include    
2.   kernel.php979   siteloader->execModules    
3.   siteloader.inc2611   forum->main    
4.   module.inc152   foselector->buildForumCache    
5.   foselector.inc665   foselector->getMainForums    
6.   foselector.inc278   MySQL->getAllRows