Question : MySQL Incremental Backup on Red Hat Linux ES4

Dear all,

Could you tell me how to change MySQL into using the "--log-bin" option so
that I can run MySQL incremental backup ?

I changed its config file : /etc/my.cnf by adding the above "--log-bin" and
have also tried enabled the "log_bin" option, and then start it again :
service mysqld restart,
but failed.

Any ideal ? Can you tell me the steps ?

My existing configuration : Red Hat Linux ES4, MySQL 4.1.20, phpMyAdmin
2.6.0-pl2