What type of clients? You should not be using net time manually or in a batch file to sync time for 2000 and XP clients.
Run 'net time /querysntp' It should say "this computer is not configured to use a specific SNTP server"
If it says something else, run 'net time /setsntp:' then restart the Windows Time service.
Net time is not the way to check for time sync on 2000 and XP clients. On 2000, you need to do the following:
net stop w32time
w32tm -v -once
net start w32time.
The w32tm output will show who the machine is syncing with.
On XP run 'w32tm /resync /rediscover /nowait' You should see a w32time event in the system log.