I had the same issue come up on a Win 2000 Pro machine. I removed TCP/IP from the NIC, restarted, re-added it, restarted again and it worked.
I installed PGP 7.03 for Windows on my Win2k Pro (with IPSEC) machine and I received events 319 and 321. My solution was to uninstall the TCP/IP protocols, reboot, reinstall TCP/IP, and reinstall Win2k SP4. After this, the problem did not appear anymore.
Failed to obtain Kerberos server credentials for ISAKMP/Oakley service. Kerberos authentication will not function. The most likely reason for this is lack of domain membership. This is normal if your computer is a member of a workgroup.
I had this error, and managed to fix it. After reinstallation of the windows 2000 high encryption pack I was able to start the ipsec policy agent again. I think this error was caused after installing a random number generator on my machine (egads).
Reinstallation of the tcp/ip protocol under windows 2000 fixed this problem.
Problem: The IPSec Policy Agent service isn't started.
Solution: Start the IPSec Policy Agent service.
Problem 2: The IPSec Policy Agent service can't be started. It fails with event ID 319 (as described above).
Solution 2: If PGPNet is installed on the machine this could be the source of the problem. Try removing PGPNet. I guess that PGPNet makes some changes to the IPSec Service on the machine. This is valid for other programs, like VPN clients.