Need help using airmon-ng

[humpy]

Hello.-)
Running BackTrack4, thru VMware and that works fine, but.....sadly I have a problem when I try to
using your tutorial on wep cracking...

I type in this into shell:
airmon-ng
(then shows: Interface Chipset Driver) but not what kind of...?
airmon-ng stop wlan0
(then shows: Interface Chipset Driver) but not what kind of...?
ifconfig wlan0 down
then I get this message: wlano:error while setting interface flags: no such device
I just dont know what to do....-(

I know My interface name wirelesscard is: RTL81390
And using Netgear usb adapter to connect to router
Actually I can go online with firefox in backtrack

Please can you help me;-)

[Archangel-Amael]

Best help available is right here:
getting_started [Aircrack-ng]
Give it the ol' twice over and let me know.