VNC giving only a light grey screen and no desktop with tightvncserver

[Lars Noodén]

I'm revisiting VNC and am either doing something wrong or finding that
something is broken with the package tightvncserver.  Have others found 
the same problem?

When I set up a VNC server on a Lubuntu host, I can connect to it via an
SSH tunnel.  I can connect from another machine or from the same host.
However, I do not get any desktop, I get instead a blank, light grey
screen with the mouse cursor as an X.  The mouse moves, but no desktop
components or menus are available.

The problem seems to be with the package tightvncserver being unable to 
run on display :0, where the desktop is.  

$ tightvncserver :0
perl: warning: Setting locale failed.
perl: warning: Please check that your locale settings:
	LANGUAGE = "en_US:en",
	LC_ALL = (unset),
	LC_CTYPE = "UTF-8",
	LANG = "en_US.UTF-8"
    are supported and installed on your system.
perl: warning: Falling back to the standard locale ("C").

Warning: lubuntu:0 is taken because of /tmp/.X0-lock
Remove this file if there is no X server lubuntu:0
A VNC server is already running as :0

Using x11vnc between the same machines works as expected.

Regards,
/Lars