xx-DOS (im)possible problem!

Hi,

we (with a friend) have succefully built a 100% free network for
use with Clipper programs :)

We use a Linux server with Samba, and FreeDos with MS-Client.
(fdxms, kernel 2027rc, FreeCom w/ xms-swap, and umbpci if possible)

Now we have a bug, but it is only more or less FreeDOS related:
it happens in FreeDOS _and_ in MS-DOS 6.22, but NOT with
MS-DOS 7.10 (Win98). This proves that it is not a FreeDOS bug,
but I would appeciate any help to UNDERSTAND it:

The problem is wit INT 17h ah=02h dx=0. after the command
    net  use  lpt1  \\server\printer
it returns ah=0D0h while it should return 090h. The strange thing 
ie that this should be a BIOS+MS-Client problem only, but
it works ok with MS-DOS 7.10 from Win98.

The bit that is set is "Acknowledge". Does anyone have a clue as
to what may be happening? Is the dos capturing int 17h to fix
an old bug?

I have the idea that a simple TSR to turn that bit off could be ok...
I have the tools to do it fairly easely, but is it really ok?
Any suggestion? I

I would appreciate any kind of help,
Alain