ExitWindowsEx + AT Service

Hi there!
I wrote a little program in order to logoff an user on a WinNT 4
workstation, using

   ExitWindowsEx(EWX_FORCE Or EWX_LOGOFF, 0)

This works fine if run locally, but not if I schedule the program on
another wkst with AT command.
More details:
- The .EXE file has been regularly copied on the wkst.
- ExitWindowsEx returns True on the wkst without logging-off!!
- Program written with Delphi 3
- AT command run with /interactive option (I see the form, click on the
logoff button, but nothing happens)

Does anybody know why?

Please, if you can, e-mail your replies, 'cause my news server clears
messages every two days.
Thanks in advance

Corrado Tasca
Polo CAD S.r.l.
Via Greto di Cornigliano, 6R
16152 - GENOVA - ITALY
E-Mail: polo...@pn.itnet.it