Windows 2K3 Authentication Problem

[xpozdwire]

I have a small domain set up on a home network. It consists of one domain controller (Win 2K3 EE) and two client XP machines with SP2. After being logged on to the domain from either client machine for about 30 minutes I can no longer access the shard disk resources on the domain controller. When I try to navigate to a shared directory I get the message, "The system detected a possible attempt to compromise security. Please ensure that you can contact the server that authenticated you." This message comes after getting hung on trying to open the folder for 30-60 seconds. If you log off then log back in it works fine. The only place I could think to fix this problem is in the kerberos policy in the GPO editor. Any advice on a possible source of this problem would be greatly appreicated.