Help with logging on Win2k domain via hardware VPN

Have t1 at different offices but can only access the
shared folders on the win2k server domain controller
located at the central office when at the central office.
I can ping the machines, but cannot "see" them when using
search for computers. Error when trying to connect: "There
are currently no logon servers aviilable to service the
logon request." I can also ping the gateway routers at
each location.

Any help greatly appreciated!

Dano