Net Time script does not seem to work

We have this as part of the logon script to sync everyone’s clock to a server:
Net Time \\server1 /set /yes

The server runs on NT4, while the clients are on XP/2000/9x.

Problem:
The script does not seem to work on Windows 2000/XP computers as they log on. Do the end users have to have administrator’s right in order for the script to take effect? We tried the same command in CMD (with users’ logon)and still wouldn’t work.
If that’s the case, is there a way to make the script work without granting users admin right?

Thanks for all input.