I have this error repeating on a W2K3 server: Event ID 4
The kerberos client received a KRB_AP_ERR_MODIFIED error from the server Client1$. The target name used was cifs/client2.mydomain.com. This indicates that the password used to encrypt the kerberos service ticket is different than that on the target server. Commonly, this is due to identically named machine accounts in the target realm (MYDOMAIN.COM), and the client realm. Please contact your system administrator.
One thing interesting to note is that the computer name mentioned in the first sentence (client1$) is not the same as the name that appears after cifs/.
The history of this server is as follows:
There was a server on the network with the same name as this server that was primarily our antivirus server. I installed a new server to replace it and its function as an antivirus server. I needed it to have the same name as the old server. I renamed the old server then took it offline. I then renamed the new server as the same name as the old server, then joined it to the domain. The new server is also a WSUS server.