Cannot find display :0.1

Question

I'm using fujitsu LH531 Laptop with ubuntu 12.04, and with secondary 1440x900 monitor attached to the VGA, confirmed by xrandr command.

The problem is, i want to run a program (vlc) to the second monitor, but can't find a way for that.

I've tried, DISPLAY=:0.1 vlc and a jumbled screen. Trying DISPLAY=:0.1 firefox, got error cannot open display 0.1.

The current condition is that the dual monitor is worked as 2 separated screen (e.g screen a showing firefox, screen b libreoffice)

Can anyone please help on this? the main goal is, how to run vlc (program) to specific monitor.

Below is the output of xrandr.

Screen 0: minimum 320 x 200, current 2806 x 900, maximum 8192 x 8192
LVDS1 connected 1366x768+0+132 (normal left inverted right x axis y axis) 309mm x 174mm
   1366x768       60.0*+
   1360x768       59.8     60.0  
   1024x768       60.0  
   800x600        60.3     56.2  
   640x480        59.9  
VGA1 connected 1440x900+1366+0 (normal left inverted right x axis y axis) 370mm x 232mm
   1440x900       59.9*+   75.0  
   1280x1024      75.0     60.0  
   1280x960       60.0  
   1152x864       75.0  
   1024x768       75.1     70.1     60.0  
   832x624        74.6  
   800x600        75.0     60.3     56.2  
   640x480        75.0     60.0  
   720x400        70.1  
HDMI1 disconnected (normal left inverted right x axis y axis)
DP1 disconnected (normal left inverted right x axis y axis)

Thanks.