cant map drive over vpn ?

Hi,

SETUP
-Windows 2000 domain (server 1) hosts active dir.
-Window 2000 member (server 2) authenticates PPTP calls, also host share
"Z", also host terminal server
-Windows 98 stand alone client

PROBLEM
-Win 98 client established connection to server 2 using PPTP. I then
attempted to map drive using the following: "net use z: \\server2\z". I got
the error "error 3787: you must log on before performing this operation"

NOTE:
- it works with win2k pro clients using "net use z: \\server2\z /user:test"
, with 98 it does not allow the "/user:" switch in the NET USE command.
- i can run terminal server client over the connection so win 98 can see
server2 no problem.
- when user in question logs on to terminal server (server2), they DO have
access to share "Z" so its not an NTFS permissions problem

May be related to some policy thing i dont know about ?

Thanks for any help.
Scott.

On one win98 clinet i ticked the "logon to network" option in the VPN
adapter proprties. This prompted the user to enter a user + pass again.
Other win98 user were not prompted however.

I cant seem to find a consistant way of doing this.

Thanks
Scott.