Something else I thought of, is the DX4000 joined to a domain? If it is, it will get it’s time from the PDC Emulator in the domain.
Otherwise, ensure the Windows Time service is running, and check the registry entries for the W32Time service, and that they are appropriate for your environment, i.e., set to domain if you are joined to a domain, or an NTP server (such as time.windows.com) if it is a stand-alone device.
See the following TechNet article:
http://technet.microsoft.com/en-us/library/cc773263(v=ws.10).aspx
