weird error on WUS server

Hi all

I am running WUS server on 2003 sp1. recently i have been noticing in the
system log on the WUS server an event id 4 that says

"The kerberos client received a KRB_AP_ERR_MODIFIED error from the server
NWPCOPC0300$. The target name used was cifs/NWSCLT0043.nwpsc.com. This
indicates that the password used to encrypt the kerberos service ticket is
different than that on the target server. Commonly, this is due to
identically named machine accounts in the target realm (NWPCO.COM), and the
client realm. Please contact your system administrator".

I dont get this error on any other machine in the forest except the WUS
server. I have two domains in the forest and i have a trust going on with
another forest.

How can i start to troubleshoot this issue and why would I only see this
error on the WUS server and not other server or DC on the network?

Many thanks