Question about authenticating CHAP clients using an external program - A different case

Hello All, I am using freeradius-1.1.7. In order to authenticate users using an external program, I have created an instance of the rlm_exec module which contains the properties of the external program. In the radiusd.conf, I have called the instance in the authentication section. Now, as I want to authenticate CHAP clients, I need to pass their clear text passwords to the rlm_chap module. The passwords are stored in the database (MySQL) and are fetched in the external program. In the external program, I have simply output User-Password = ### as the user's clear text password, but the rlm_chap module says: "Could not find clear text password for user ...". What is wrong? Any ideas? Kind Regards Ali Majdzadeh Kohbanani