[FreeNX-kNX] I'm having trouble shadowing a current running session with VNC

[Linux User]

When I'm trying to connect to display -- :0 with nxclient using Desktop VNC 
from what I can understand how it works, however it fails on the client side 
with Error: Failure reading from the peer proxy. On the server side

04/11/2009 00:30:46 passing arg to libvncserver: -rfbauth                            
04/11/2009 00:30:46 passing arg to libvncserver: /home/lhorace/.nx/C-
comp2-1000-6D0A3517E36FD4124689D197B4375B9C/scripts/.passwd
04/11/2009 00:30:46 x11vnc version: 0.9.8 lastmod: 2009-06-14                                                                   
Info: Proxy running in server mode with pid '23202'.                                                                            
Info: Waiting for connection from '127.0.0.1' on port '5000'.                                                                   
Info: Accepted connection from '127.0.0.1'.                                                                                     
Warning: Connected to remote version 3.4.0 with local version 3.2.0.                                                            
Warning: Consider checking http://www.nomachine.com/ for updates.                                                               
Info: Connection with remote proxy completed.                                                                                   
Info: Using LAN link parameters 1536/24/1/0.                                                                                    
Info: Using agent parameters 5000/0/50/0/0.                                                                                     
Info: Using pack method 'none' with session 'vnc'.                                                                              
Info: Not using NX delta compression.                                                                                           
Info: Not using ZLIB data compression.                                                                                          
Info: Not using ZLIB stream compression.                                                                                        
Info: Not using a persistent cache.                                                                                             
Info: Listening to X11 connections on display ':1000'.                                                                          
Info: Established X client connection.                                                                                          
TightVNC Viewer version 1.3.9                                                                                                   

Usage: /usr/bin/vncviewer [<OPTIONS>] [<HOST>][:<DISPLAY#>]
       /usr/bin/vncviewer [<OPTIONS>] [<HOST>][::<PORT#>]  
       /usr/bin/vncviewer [<OPTIONS>] -listen [<DISPLAY#>] 
       /usr/bin/vncviewer -help                            

<OPTIONS> are standard Xt options, or:
        -via <GATEWAY>                
        -shared (set by default)      
        -noshared                     
        -viewonly                     
        -fullscreen                   
        -noraiseonbeep                
        -passwd <PASSWD-FILENAME> (standard VNC authentication)
        -encodings <ENCODING-LIST> (e.g. "tight copyrect")     
        -bgr233                                                
        -owncmap                                               
        -truecolour                                            
        -depth <DEPTH>                                         
        -compresslevel <COMPRESS-VALUE> (0..9: 0-fast, 9-best) 
        -quality <JPEG-QUALITY-VALUE> (0..9: 0-low, 9-high)    
        -nojpeg                                                
        -nocursorshape                                         
        -x11cursor                                             
        -autopass                                              

Option names may be abbreviated, e.g. -bgr instead of -bgr233.
See the manual page for more information.                     
04/11/2009 00:30:52 XOpenDisplay("127.0.0.1:0.0") failed.     
04/11/2009 00:30:52 Trying again with XAUTHLOCALHOSTNAME=localhost ...

04/11/2009 00:30:58 ***************************************
04/11/2009 00:30:58 *** XOpenDisplay failed (127.0.0.1:0.0)

*** x11vnc was unable to open the X DISPLAY: "127.0.0.1:0.0", it cannot 
continue.
*** There may be "Xlib:" error messages above with details about the failure.    

Some tips and guidelines:

** An X server (the one you wish to view) must be running before x11vnc is
   started: x11vnc does not start the X server.  (however, see the -create
   option if that is what you really want).                               

** You must use -display <disp>, -OR- set and export your $DISPLAY
   environment variable to refer to the display of the desired X server.
 - Usually the display is simply ":0" (in fact x11vnc uses this if you forget
   to specify it), but in some multi-user situations it could be ":1", ":2", 
   or even ":137".  Ask your administrator or a guru if you are having       
   difficulty determining what your X DISPLAY is.                            

** Next, you need to have sufficient permissions (Xauthority) 
   to connect to the X DISPLAY.   Here are some Tips:         

 - Often, you just need to run x11vnc as the user logged into the X session.
   So make sure to be that user when you type x11vnc.                       
 - Being root is usually not enough because the incorrect MIT-MAGIC-COOKIE  
   file will be accessed.  The cookie file contains the secret key that     
   allows x11vnc to connect to the desired X DISPLAY.                       
 - You can explicitly indicate which MIT-MAGIC-COOKIE file should be used   
   by the -auth option, e.g.:                                               
       x11vnc -auth /home/someuser/.Xauthority -display :0                  
       x11vnc -auth /tmp/.gdmzndVlR -display :0                             
   you must have read permission for the auth file.                         

** If NO ONE is logged into an X session yet, but there is a greeter login
   program like "gdm", "kdm", "xdm", or "dtlogin" running, you will need  
   to find and use the raw display manager MIT-MAGIC-COOKIE file.         
   Some examples for various display managers:                            

     gdm:     -auth /var/gdm/:0.Xauth
              -auth /var/lib/gdm/:0.Xauth
     kdm:     -auth /var/lib/kdm/A:0-crWk72
              -auth /var/run/xauth/A:0-crWk72
     xdm:     -auth /var/lib/xdm/authdir/authfiles/A:0-XQvaJk
     dtlogin: -auth /var/dt/A:0-UgaaXa

   Sometimes the command "ps wwwwaux | grep auth" can reveal the file 
location.

   Only root will have read permission for the file, and so x11vnc must be run
   as root (or copy it).  The random characters in the filenames will of 
course
   change and the directory the cookie file resides in is system dependent.

See also: http://www.karlrunge.com/x11vnc/faq.html