Xvfb sous linux

Bonjour,
j'ai essayé d'installer xvfb sous linux comme il a indiquer dans cet article

http://www-12.lotus.com/ldd/doc/uafiles.nsf/docs/LMS105/$File/ReadMe.html#xvfb

et voila les resultat/

superuser@asterisk59:~$ ps -ef|grep Xvfb
1001 15453 1 0 Jul27 ? 00:00:00 /usr/X11R6/bin/Xvfb :8101 -ac
1001 14538 1 0 Jul29 ? 00:00:00 /usr/bin/Xvfb :1
1001 15420 1 0 Jul29 ? 00:00:00 /usr/bin/Xvfb :10 -screen 0 800x600x16
1001 18239 16191 0 10:34 pts/8 00:00:00 grep Xvfb


superuser@asterisk59:~$ echo $PATH
/opt/jdk1.6.0_06/bin:/usr/local/bin:/usr/bin:/bin:/usr/games
superuser@asterisk59:~$ PATH=$PATH:/usr/X11R6/bin/Xvfb
superuser@asterisk59:~$ echo $PATH
/opt/jdk1.6.0_06/bin:/usr/local/bin:/usr/bin:/bin:/usr/games:/usr/X11R6/bin/Xvfb
superuser@asterisk59:~$ /etc/rc3.d/S75xvfb start
***Starting up the Virtual Frame Buffer on Screen 1***
Fatal server error:
Server is already active for display 1
If this server is no longer running, remove /tmp/.X1-lock
and start again.

merci davance