Oki, I have tried to install kde instead of xfce and no error occurs.
It is working by VNC.
I have then compiled and installed XBMC without any problem, but it does not work.
When I enter xbmc" in the shell, it returns:
Xlib: extention "RANDR" missing on display ":1.0"
RandR extension missing
I have tried then to export DISPLAY=":0.0" (which does not seem to be right, because vncserver is running on 1:0) and then the shell returns
Cannot get root display. Is X11 running and is your DISPLAY variable set?
Indeed, as I am running via VNC, and not directly to the graphic server, X11 can as well appear as not running.
Is there any trick to workaround this issue?
Or, is it possible to provide the direct access to the graphic server and the graphic card to DomU instead of Dom0?
I am sure it is possible, because the structure of the DomU and Dom0 is basically the same with paravirtualization, with Dom0 is only provided tools to control the DomUs.
But I don't know how to make the graphic server connect directly to the hardware.
Thanks a lot for your help and answers! Any kind of documentation related to my issue would be very helpful!