rlm_exec and authentication

[Oguzhan Kayhan]

Hello all,
I wanna write an authentication script which will control the 
username&password pair  from an IMAP server. Acutally the script is about 
ready but, i couldt find a way to execute from radius.
I first tried rlm_perl which i thouhgt it will be better and easier
But i had the error 

"undefined symbol: Perl_Tstack_sp_ptr (failed! run '/usr/sbin/freeradius
-x' to find out why.)"

Then i reinstalled freeradius checked the updates of perl etc but no 
solution..
And i decided to use rlm_exec for that. But i am not sure how will i use it as 
authentication.
Anybody has an example regarding to that? Or even a solution for my rlm_perl 
Thank u


Oguzhan Kayhan