[Samba] net ads join error

[spike1197]

This is more than likely a rookie config problem but when I try to add
the server to the ADS domain with:
$net ads join
I get:
[*DATESTAMP*] libads/kerberos.c:get_service_tickets(335)
  get_service_ticket: kerberos_kinit_password
SERVER$MY.DOMAIN.COM at MY.DOMAIN.COM failed: Preauthentication failed
Segmentation fault

Redhat ES 3. samba-3.0.10

my /etc/krb5.conf was taken from another machine that it works on..
same os.. same samba level...