Xvfb strange problem

[GUERRAZ Francois]

Hello,

For one of our client's server, we use Xfvb. It is launched in a startup
script in 800x600x32 resolution.
Recently they halted (violently I guess) the system. After the reboot,
we haven't been able to restart Xvfb, it kept failing w/ this message :

"Fatal server error:
Couldn't add screen 0"

So we tried to launch Xvfb in 800x600x16 and now it works like this !

Of course, our client asks us why did we had to make this change. Could
you help me to answer them please? :)

We used to launch Xvfb with this command line :
# nohup /usr/X11R6/bin/Xvfb :25 -screen scrn 800x600x32 &

I think there is a bug in it? What the hell is "scrn"??? And why DID it
worked? Now it works with 
# nohup /usr/X11R6/bin/Xvfb :25 -screen scrn 800x600x16 &

Regards,

François.