SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: SELECT a.replycount AS replies,a.boardid AS boardparentid,a.threadid AS threadid,a.topic AS threadname FROM bb1_threads AS a,bb1_boards AS b WHERE a.boardid = b.boardid && b.invisible='0' ORDER BY a.replies DESC LIMIT 10
mysql error: Unknown column 'a.replies' in 'order clause'
mysql error number: 1054
mysql version: 4.1.22-nmm-1-log
php version: 5.2.12-nmm2
Date: 06.02.2012 @ 00:21
Script: /statistik.php
Referer: