Changing password on linux machine hangs

[M]

Hi:

We use Active Directory to create User accounts and make the person
change his/her password the first time he/she logs on to any of our
machines (linux or windows). Changing password on the Windows machines
works just fine but no one can change their passwords on a linux
machine. Not just the first time, but ever.

[user at machine ~]$ passwd
Changing password for user username.
Kerberos 5 Password:
New UNIX password:
Retype new UNIX password:

After this it just hangs. The password never gets changed. i found
pre-authentication failure kadmin/changepw...failure code 0x19. in the
kdc admin-server event log which corresponds to "additional
pre-authentication required." I googled that but couldn't find a way
to fix that failure. I don't see anything in the logs on the linux
machine that I'm trying to change my password on.

Maybe its a pam issue but I have no idea how and where to begin fixing
it. Any help will be greatly appreciated. I've ruled out firewall
issues.

Thanks

qassair