Firesheep in BackTrack 4R1

1) Update your firefox,follow this nice step-by-step guide to do it.
2) Now download firesheep plugin from here . (thx to jnew from github)
3) Open your firefox and go to Tools -> Add-ons -> Extensions and drag there a firesheep plugin.
4) Run Ettercap and start sniffing.
5) Go back to your firefox check the firesheep preferences and hit the "Start Capturing" button!