i really need some clarification about where and how logins are used & verified.

am running a VFP6 app on various remote laptops (WIN95, WIN98, WINME, WIN2000)
that (using Mabry RASX.OCX) perform dial-up networking to connect to an NT4
server.  i set all the connection properties for the RASX control (username,
password, dun-connection-name, etc) and i can connect just fine, and can
invoke my RPC server just fine.

(on the server, i have created separate shared directories for each client).

in the same VFP6 app, i copy files to and from the appropriate share using
the COPY FILE command, using UNC for server filespecs and device/path style
for laptop file specs.  however, to actually be able to do that copy, i have
found it necessary (on the remote laptops) to (create and) login to the
laptop with a username and password that matches the username & password
on the NT4 server.

question 1) ONLY FOR LAPTOPS RUNNING WIN98  !!! i have to NOT login into
            the (laptop) windows username & password. is that common
            knowledge that i missed ?
            or do i just have a fluke setup for WIN98 on that machine ?

question 2) the whole arrangement works, but i don't understand why i need
            to specify a windows username/password on the laptop. am i not
            already logged on to NT4 when i make the DUN connection ? if
            not, is there some way to programatically log on to the server
            without having to set up a windows username/password on
            the remote laptop ?

question 3) it does NOT work if, on the remote laptop, i have booted
            into a hardware profile with a NIC enabled.  does that
            make sense ?  it does not even seem to matter that i am
            not actually docked or logged on to a network with the 
            laptop ?? or am i going about this wrong ?