Member server forgets DNS

Sorry about the vague title. I have installed a Windows 2003 member server on our network. The DC is also a 2003 box. When I reboot the new box, everything is fine for a couple of days and then suddenly, it can no longer find the DC. i.e. users who don’t have previously cached profiles cannot log in and nobody can log in via terminal services. I have installed numerous XP workstations and Win2K member servers on this network without any problem. Some have been running over a year now, but this is the first 2003 member server I have installed. The 2003 DC was in place when I inherited the network.

As far as I can tell, the locally cached DNS SVR record for the DC expires and for some reason requests for a new service record go un answered.