The normal solution would be as follows:

export DISPLAY=:0.0

/usr/lib/vino/vino-server &

But what happens if that doesn't work?  I haven't been able to find much documentation about how to find the list of displays and how their numbering works in Xorg.

Sometimes you'll get this error when trying to restart vino:

Cannot open display:

For some reason my display is not on 0.0, maybe it's because I restarted X a few times:

View a list of all X displays:

ls /tmp/.X*-lock

/tmp/.X10-lock  /tmp/.X11-lock  /tmp/.X12-lock  /tmp/.X13-lock  /tmp/.X14-lock  /tmp/.X15-lock  /tmp/.X1-lock  /tmp/.X2-lock  /tmp/.X3-lock  /tmp/.X4-lock

I exported each one manually and restarted vino-server until I found that mine was 4.0 (if you use X2 or X4 lock) then you need to pass it as 2.0 or 4.0 or X10 is 1.0 etc...

export DISPLAY=:4.0

/usr/lib/vino/vino-server&
[1] 3854
$ 04/09/2011 12:14:04 PM Autoprobing TCP port in (all) network interface
04/09/2011 12:14:04 PM Listening IPv{4,6}://*:5900
04/09/2011 12:14:04 PM Autoprobing selected port 5900
04/09/2011 12:14:04 PM Advertising security type: 'TLS' (18)
04/09/2011 12:14:04 PM Advertising authentication type: 'VNC Authentication' (2)
04/09/2011 12:14:04 PM Advertising security type: 'VNC Authentication' (2)

(vino-server:3854): Gtk-WARNING **: Error parsing gtk-icon-sizes string:
    'panel-menu=24,24
panel=20,20
gtk-button=18,18
gtk-large-toolbar=24,24'