One of the most recent problems I stumbled upon while running Backtrack, or any other linux distro for that matter is setting the region on a wireless card. The typical procedure is :
[raw]iwconfig wlan0 channel 13[/raw]
And commonly you will get
[raw]error for wireless regquest ”set frequency”
set failed on device wlan0 ; invalid arugment[/raw]
There is an easy fix for this that will allow you to change the region mode your wireless adapter is in.
[raw]iw reg set FR[/raw] [raw]iw reg set US[/raw]
More on IW here.