[FreeNX-kNX] NXClient crashes minimal x-system

[Mario Fux]

Good morning

I trying to install a minimum x-system for clients which serve only as 
"NX-terminals".

After a raw debian installation I installed the following components beneath 
the NXClient:
apt-get install xserver-xfree86 libxrender1 libsm6 libxext6 libstdc++6 
libstdc++2.10-glibc2.2 xbase-clients x-window-system-core

Then I created a .xsession file with one line:
/usr/NX/bin/nxclient

Ok, it works so far and the nxclient appears. I then configure an NX session 
and login. The window appears (with the NX red and white logo) and then x 
crashes.

Can you say me what's wrong there, please?

What I already tried:
- I configured fullscreen and fixed resolutions (e.g. 1024x768, etc.). The 
appearing window is at the configured size but x crashes as well.
- I thought the a window manager is needed on so I installed twm. X works with 
twm but I don't know yet how to autostart NXClient inside twm.

thx for your help
Mario