[winswitch] Forwarding a whole desktop throwing error

[vrkorada at yahoo.co.in]

Hi,

I used the following syntax specified in http://xpra.org/trac/wiki/Usage

xpra start :123 --start-child="Xephyr :234 -ac -screen 800x600" DISPLAY=:234 start-kde



and here is the output:

koradav at toy01.nyc:/u/koradav/Documents> xpra start :123 --start-child="Xephyr :234 -ac -screen 800x600" DISPLAY=:234 start-kde

Usage: 

                xpra start DISPLAY

                xpra stop [DISPLAY]

                xpra list

                xpra upgrade DISPLAY

                xpra attach [DISPLAY]

                xpra detach [DISPLAY]

                xpra screenshot filename [DISPLAY]

                xpra info [DISPLAY]

                xpra version [DISPLAY]

                xpra shadow DISPLAY





xpra: error: need exactly 1 extra argument





Am I doing something wrong? 



Thanks,
Venkat