I found that the security settings on our Windows 2003 DNS server included a record for the administrator with read only access. I removed this incorrect entry and the error has stopped.
This may occur on Windows 2000 computers that are members of a Windows 2000 Active Directory domain but their DNS domain do not match the one configured for the Active Directory.
This is caused by the attempt to dynamically register the DNS records on DNS servers that do not support this operation (i.e. your ISP servers). One can disable this behaviour by following the instructions on ME178148
In our environment, this occurred when users would log onto the Exchange domain (ex2k.com) and this would become thier primary DNS suffix. Then, when thier machine tried to update the DNS for thier zone (user.com) it couldn't. To fix, run ipconfig /flushdns and reboot. Make sure to log into the registration domain before any other.
The DNS tab for the network adapter is configured to register the PC with DNS (and the DNS servers do not support this). To change the setting, open the TCP/IP properties, select the ADVANCED button, navigate to the DNS tab and clear the check box at the bottom to not register dynamically.