Hi,
It looks like you DC lost its secure channel/machine password with the domain.
Please reset it using the following two steps:
First, purge the pre-exisiting kerberos tickets using Resource kit tool, either Klist or kerbtray
Second, stop and disable KDS service on the DC
Third, reset the secure channel with help of netdom
netdom resetpwd /server:IP of PDC Emulator /UserD: Domain\Administrator PasswordD:*
<Enter>
Next prompt type in the password (it would be invisible)
Note: The filed PasswordD comes with an extra D :)
HTH
Saurabh