求助：mysqld_safe 启动不了

luotell

mysqld_safe启动的时候出错。
下面是错误日志，各位高手看看。
080222 20:01:47  mysqld started
080222 20:01:47  InnoDB: Database was not shut down normally!
InnoDB: Starting crash recovery.
InnoDB: Reading tablespace information from the .ibd files...
InnoDB: Restoring possible half-written data pages from the doublewrite
InnoDB: buffer...
080222 20:01:47  InnoDB: Starting log scan based on checkpoint at
InnoDB: log sequence number 0 43634.
InnoDB: Doing recovery: scanned up to log sequence number 0 43634
080222 20:01:47  InnoDB: Flushing modified pages from the buffer pool...
080222 20:01:47  InnoDB: Started; log sequence number 0 43634
080222 20:01:47 [ERROR] /usr/libexec/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
080222 20:01:47 [ERROR] /usr/libexec/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
080222 20:01:47 [ERROR] Fatal error: Can't open and lock privilege tables: Can't
find file: './mysql/host.frm' (errno: 13)
080222 20:01:48  mysqld ended

yueliangdao0608

080222 20:01:47 [ERROR] /usr/libexec/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
080222 20:01:47 [ERROR] /usr/libexec/mysqld: Can't find file: './mysql/host.frm'
(errno: 13)
080222 20:01:47 [ERROR] Fatal error: Can't open and lock privilege tables: Can't