Netlogon Failure – Samba as PDC on 10.3.8 Server

We have a G5 running OS X Server 10.3.8. The Samba service (3.0.5) running on it is the primary domain controller (PDC) for two Windows 2000 Servers and around 25 Windows XP desktops. These domain members are reporting a slew of errors in their System logs. The following message appears every 4 hours:

Source: NETLOGON 
Type: Error 
Event ID: 3224 

"Changing the machine account password for account JASONHEISER$ failed with the following error: A device attached to the system is not functioning."

This is a non-fatal error. However, this error (I think) eventually culminates into a more critical problem:

Source: Netlogon 
Type: Error 
Event ID: 3210 

"Failed to authenticate with \\\\MRWINT, a Windows NT or Windows 2000 domain controller for domain CPI." 

This is a fatal error. The computer can no longer authenticate itself to anything on the domain. The computer must then reboot.

It takes a while for this authentication failure to occur. Most of the XP workstations are shut down each night and never experience it. The Windows 2000 Servers, which are running 24/7, succumb to this error every 1-4 weeks. Since they handle print services and our ERP software, this failure is a showstopper.

Help. Please.