Win2000Server – system time

I have a Windows 2000 Server which show the correct date/time and I use it for time synchronization in our network.
– From a WinXP workstation, if I check the time with “net time \\server” command, all it’s OK.
– From a WinNT workstation with the same command it show a different time (-1h).
What can be wrong?
Thank you.