phpBB : Critical Error

Error doing DB query userdata row fetch

DEBUG MODE

SQL Error : 144 Table './schradthp/phpbb_sessions' is marked as crashed and last (automatic?) repair failed

SELECT u.*, s.* FROM phpbb_sessions s, phpbb_users u WHERE s.session_id = '9c4b6fea8bb1fb8c11ba8d5ca5c5dca8' AND u.user_id = s.session_user_id

Line : 325
File : sessions.php