wine users - Mar 2005 - Setup.exe: Could not determine the operating system

Hi!
  I'm trying to install a specialized proprietary program, which should be
run
under NT 4.0. When I start the installer from wine, it launches but very soon
it writes: "Cannot determine the operating system. Exiting." and it
really
exits.
  It's the fake windows install but with some native DLLs copied. In the
config
file, version is set to nt40, but it doesn't work either.
  How to find what else to simulate to let the program feel it runs on nt40 ?
                      With regards, Pavel Troller