[FreeNX-kNX] Virtual Desktop appears, and then POOF it goes away!

[Steven Maddox (Architect)]

Hi Folks,

I am setting up FreeNX on a Debian 4 box for a friend.  I have got all 
the usual packages off the repository stated on the main FreeNX web site 
and it installed and set up correctly.

Output of nxsetup...
-------------------------------------------------------------------------------
         FreeNX guesses that you want to _install_ the server.
         Type "y" to abort the installation at this point in time.
         "N" is the default and continues installation.
         Use "/usr/sbin/nxsetup --help" to get more detailed help hints.

  Do you want to abort now? [y/N] N

------> It is recommended that you use the NoMachine key for
         easier setup. If you answer "y", FreeNX creates a custom
         KeyPair and expects you to setup your clients manually.
         "N" is default and uses the NoMachine key for installation.

  Do you want to use your own custom KeyPair? [y/N] N
Setting up /etc/nxserver ...done
Setting up /var/lib/nxserver/db ...done
Setting up /var/log/nxserver.log ...done
Setting up known_hosts and authorized_keys2 ...done
Setting up permissions ...done

----> Testing your nxserver configuration ...
Warning: Invalid value "COMMAND_START_KDE=startkde"
          Users will not be able to request a KDE session.
Warning: Invalid value "COMMAND_START_GNOME=gnome-session"
          Users will not be able to request a Gnome session.
Warning: Invalid value "COMMAND_START_CDE=cdwm"
          Users will not be able to request a CDE session.

   Warnings occured during config check.
   To enable these features please correct the configuration file.

<---- done

----> Testing your nxserver connection ...
HELLO NXSERVER - Version 1.4.0-45-SVN OS (GPL)
NX> 105 quit
Quit
<--- done

Ok, nxserver is ready.

PAM authentication enabled:
   All users will be able to login with their normal passwords.

   PAM authentication will be done through SSH.
   Please ensure that SSHD on localhost accepts password authentication.

   You can change this behaviour in the /etc/nxserver/node.conf file.
Have Fun!
-------------------------------------------------------------------------------

So that looks fine, ultimately the problem is that when I try to connect 
using my NX client on windows... the virtual desktop (i.e. the black box 
with the NX logo) displays and then simply goes away again.  I just get 
a box saying 'No response received from the remote server.  Do you want 
to terminate the current session' then after 'The connection with the 
remote sever was shut down'.

Any ideas on what might be wrong?

Cheers

Steven