Mysql cdr dose not work

I have installed Asterisk 1.4.5, asterisk-addon 1.4.2 create the asterisk database and cdr table, and made the proper change to /etc/asterisk/cdr_mysql.conf.

and load the cdr_addon_mysql.so in /etc/asterisk/modules.conf.

restart asterisk, in cli, cdr status return the following result.

CDR logging: enabled
CDR mode: simple
CDR registered backend: cdr-custom
CDR registered backend: cdr_manager
CDR registered backend: csv

why CDR registered backend: mysql dose not exit

Thanks suggetion

thanks

check your log files. /var/log/asterisk

After I reboot the system, it works.

Thanks