[Samba] System error 1240

[Hindy Malek]

When using Dos command:
net use Z: \\servername\public
I get prompted for a user name and password.  I have admin priveleges and have tried using user root, user admin, user guest, my own account etc.  And I get 
System error 1240 has occurred.
The account is not authorized to log in from this station.
What could be causing this?
This is happening via a remote connection from my laptop using our VPN.  When I use my computer local in the office, I have no problem mapping the drive connecting using root login.
Any help is greatly appreciated!
Hindy
hindy at onestepup.com