System error 1351 connecting over VPN

We are sharing some files with a partner firm using a Ipsec VPN tunnel.

Using this command:

net use \\10.1.1.50\cincydata\ED\Mux\Mux1202\Revit\central

Some of the computers in the office connect without complaint, but
others throw this error:

System error 1351 has occurred.

Configuration information could not be read from the domain
controller, either because the machine is unavailable or access has been
denied.

No events are logged.

I haven't been able to uncover any blatant differences between the
machines that can connect and those that can't. Doesn't seem to be
related to OS (we have XP-32, XP-64 and Vista-64 here), or whether the
user has admin privileges or not.

On line information about this error doesn't seem to cover my
situation, as I can' see how it would be a dns issue, since I'm using
the IP address.

I don't know much about the server on the other side, except its a
windows server, but since some computers can connect and some cannot, I
tend to think it's a workstation configuration issue.

Any ideas would be appreciated

Jim Helfer
WTW Architects