Could not link driver rlm_sql_mysql

["johnson elangbam" <elangbamjohnson@gmail.com>]

Hi Alan,
            Thanks for helping me in configuring my freeradius with mysql. I've uncommented the "sql" in the file  /usr/local/etc/raddb/sites-enabled/default . And now I've seen message trying to commucinate with mysql. But still there is a problem of not getting the mysql driver. I am using MySql 4.1.2. Please suggest to work out. Here is the piece of output emphasizing the errors. 

rlm_sql (sql): Could not link driver rlm_sql_mysql: rlm_sql_mysql.so: cannot open shared object file: No such file or directory
rlm_sql (sql): Make sure it (and all its dependent libraries!) are in the search path of your system's ld.
/usr/local/etc/raddb/sql.conf[22]: Instantiation failed for module "sql"
/usr/local/etc/raddb/sites-enabled/default[123]: Failed to find module "sql".
/usr/local/etc/raddb/sites-enabled/default[33]: Errors parsing authorize section.

With Regards,
Elangbam Johnson