Plesk 8.1 Problem

[LinkinTurk]

Hello
I use Suse 10.1 server with Plesk 8.1.
All sites are working
And mysql server working.
But I can not access plesk.
It gives that error.
Please hepl javascript:smilie('')
confused

ERROR: PleskMainDBException
MySQL query failed: Lost connection to MySQL server during query

0: /usr/local/psa/admin/plib/common_func.php3:213
db_query(string 'select param, val from misc')
1: /usr/local/psa/admin/plib/common_func.php3:492
get_param(string 'mysql41_compatible')
2: /usr/local/psa/admin/plib/common_func.php3:389
db_set_names()
3: /usr/local/psa/admin/plib/common_func.php3:368
db_connect_real(string 'localhost', string 'admin', string '*********', string 'psa')
4: /usr/local/psa/admin/plib/common_func.php3:348
db_connect()
5: /usr/local/psa/admin/auto_prepend/auth.php3:87