SQL-DATABASE ERROR

Database error in WoltLab Burning Board: 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
Date: 09.09.2010 @ 12:19
Script: /wbb2/statistik.php
Referer: