SSH1 and SSH2 Keys Auth

Hello,

I have a Script which uses Rsync with SSH Authentication to copy files from
one server to another. It is a cronjob which executes every hour. The
servers uses the DSA public Keys to Authenticate each other. So No passwd is
asked while the cronjob is executed.

Suddenly from couple of hours it started asking for the passwd from the
cronjob and hence cannot rsync.

I am not looking for the solution from this list but could anyone suggest me
where should i look what could be wrong. I checked from the prompt to
connect to the same server but even then it asks for passwd.

I did a search in Google but it tell me how to setup the Auth.

Pls put me on correct path.

Regards,
Tina.