MySQL down on debian 6.0.7

Hi,

Suddenly my MySQL refuses to run for no reason understandable for me :-(

I hope someone knows what to do and thanks for all suggestions.

/Martin

# lsb_release -a
No LSB modules are available.
Distributor ID:    Debian
Description:    Debian GNU/Linux 6.0.7 (squeeze)
Release:    6.0.7
Codename:    squeeze

# mysqld --verbose
131012 22:37:10 [Note] Plugin 'FEDERATED' is disabled.
mysqld: Table 'mysql.plugin' doesn't exist
131012 22:37:10 [ERROR] Can't open the mysql.plugin table. Please run mysql_upgrade to create it.
131012 22:37:10  InnoDB: Initializing buffer pool, size = 8.0M
131012 22:37:10  InnoDB: Completed initialization of buffer pool
131012 22:37:10  InnoDB: Started; log sequence number 1 231236246
131012 22:37:10 [ERROR] Fatal error: Can't open and lock privilege tables: Table 'mysql.host' doesn't exist

My MySQL database directory looks a bit small ?

root@20dage:/var/lib/mysql/mysql# ls -al
total 44
drwx------ 2 mysql mysql 4096 Sep 11 23:38 .
drwx------ 8 mysql mysql 4096 Oct 12 22:51 ..
-rw-rw---- 1 mysql mysql   65 Aug 23 10:48 db.opt
-rw-rw---- 1 mysql mysql   35 Oct 11 03:25 general_log.CSM
-rw-rw---- 1 mysql mysql    0 Sep 11 23:38 general_log.CSV
-rw-rw---- 1 mysql mysql 8776 Sep 11 23:38 general_log.frm
-rw-rw---- 1 mysql mysql   35 Oct 11 03:25 slow_log.CSM
-rw-rw---- 1 mysql mysql    0 Sep 11 23:38 slow_log.CSV
-rw-rw---- 1 mysql mysql 8976 Sep 11 23:38 slow_log.frm