SQL-DATABASE ERROR

Database error in WoltLab Burning Board (2.1.5): Invalid SQL: SELECT * FROM bb2_posts WHERE postid = '3923'
mysql error: Out of resources when opening file './usr_web1_15/bb2_posts.MYD' (Errcode: 24)
mysql error number: 23
mysql version: 5.5.47-0+deb6u1-log
php version: 5.3.3-7+squeeze29
Date: 04.07.2020 @ 14:34
Script: /thread.php?postid=3923
Referer: