Common error messages with XWindowSystem
Xlib: connection to :0.0 refused by server
Xlib: connection to :0.0 refused by server Xlib: Client is not authorized to connect to Server Application initialization failed: couldn't connect to display :0.0
The X-server refused to be the display for the program you started, this usually happens when you changed to another user-id with su or when you're remotely logged in to another host.
This normally happens to me when I've su'd to 'root'. Solutions:- use "ssh -X"
or use sudo.
or Try exit from 'root' and enter 'xhost +localhost'. Afterwards, I can su back to 'root' and execute the program. There are certain security implications in doing this. man xhost for more information. -- StephenHargrove
See also: XWindowSystem