SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.3.6): Invalid SQL: SELECT postid, attachments FROM bb1_posts WHERE threadid = '5707' AND visible=1 ORDER BY posttime ASC LIMIT 0, 20
mysql error: Table './twhclub_wbb236/bb1_posts' is marked as crashed and last (automatic?) repair failed
mysql error number: 144
mysql version: 5.5.33a-MariaDB-1~squeeze
php version: 5.3.28
Date: 02.09.2014 @ 11:07
Script: /wbb2/thread.php?threadid=5707
Referer: