kinit doesn't know what login name to use, so it tries the current user (probably root) but that login name does not exist in the KDC database because that's a Windows domain controller. Try using a login name that Windows knows about:
$ kinit
Administrator@LAN.ATC.NOPassword for Administrator@LAN.ATC.NO:
If you specify the correct password, you should now have a kerberos ticket in the cache:
$ klist
Ticket cache: FILE:/tmp/krb5cc_0
Default principal:
Administrator@LAN.ATC.NOValid starting Expires Service principal
05/11/09 17:26:16 05/12/09 03:24:38 krbtgt/LAN.ATC.NO@LAN.ATC.NO
renew until 05/12/09 17:26:16
Finally, try "kinit" again without no parameters:
$ kinit
Password for Administrator@LAN.ATC.NO:
This solution worked for me on two completely different networks, but please keep in mind that there are about two million other things that could be wrong, so don't blame me if it doesn't work for you. Would love to hear about it either way though :-)