Net time / Net use – logon scripts

We are on an NT4 sp6 network.
I am trying to synch the time for my NT4/2000 workstations with my PC through a logon script. In addition, I map our network drive through the use of the same logon script.

net time \\mypcname /set /yes
net use o: \\ourPDC\networkshare /y
net use p: \\fileserver\networkshare

Net time does not work and my users receive a system error 53 – network path not found

Net use works fine but on PCs where the drives are already mapped the user receives a system error 85 – the local device name is already in use

My question is:
A: How can I get Net time to synch the workstations to my PC?

B: How can I get Net use to stop displaying error messages if the drives are already mapped?