ERROR: PleskMainDBException

[Budget101]

My sites were working fine until yesterday, now I am unable to log in to plesk, I get the following error:

ERROR: PleskMainDBException
MySQL query failed: Can't find file: './psa/misc.frm' (errno: 5)

0: /usr/local/psa/admin/plib/common_func.php3:229
db_query(string 'select param, val from misc')
1: /usr/local/psa/admin/plib/common_func.php3:467
get_param(string 'mysql41_compatible')
2: /usr/local/psa/admin/plib/common_func.php3:364
db_set_names()
3: /usr/local/psa/admin/plib/common_func.php3:343
db_connect_real(string 'localhost', string 'admin', string '**********', string 'psa')
4: /usr/local/psa/admin/plib/common_func.php3:323
db_connect()
5: /usr/local/psa/admin/auto_prepend/auth.php3:85


How can I resolve this??