Cannot start mysql on redhat through "service" command

Hello,
I'v installed mysql 5.0
(MySQL-server-standard-5.0.27-0.rhel4.i386.rpm) on RedHat AS4.
When I start mysql through command line (i.e. /usr/bin/mysqld_safe
--datadir=/var/lib/mysql --pid-file=/tmp/mysql.pid & ), everything is
ok. But when I use "service mysql start" command launch it, mysql just
quit silently.

The log file report is:

061031 11:31:35 mysqld started
061031 11:31:35 mysqld ended

And the command line report:

Starting mysqld daemon with databases from /var/lib/mysql
STOPPING server from pid file /tmp/mysql.pid
061031 12:01:18 mysqld ended

What can I do to find the problems?