SQL-DATABASE ERROR

Database error in WoltLab Burning Board: Invalid SQL: SELECT * FROM bb1_groups WHERE default_group = 1
mysql error: Can't open file: './usrdb_lunanet2_5/bb1_groups.frm' (errno: 24 - Too many open files)
mysql error number: 1016
Date: 11.08.2022 @ 00:35
Script: /forgotpw.php?sid=1dfbb2ba84b20b7a7560d7d7e05eff6a
Referer: