I'am trying to use airtune-ng to sniff an ap....

I do:
airmon-ng start wlan0
##got this error
""===> wlan0 iwl3945 - [phy0]/usr/sbin/airmon-ng: 833: cannot create /sys/class/ieee80211/phy0/add_iface: Directory nonexistent
mon0: ERROR while getting interface flags: No such device

(monitor mode enabled on mon0)

bonicideur@SilentHill:~$ Error for wireless request "Set Mode" (8B06) :
SET failed on device mon0 ; No such device.
"airodump-ng -w w -c 10 wlan0"
"modprobe tun"
"airtun-ng -a 00:11:22:33:44:55 -w 75:67:98:45:65 wlan0"

And when I type "ifconfig at0 up" my laptop freeze......ans i need to reboot

My config: intel 3945abg iwl3945
i've tried with the ipwraw driver and I've got the same crach.....

Does this come from my wifi card, and if yes is it something that I can fix...

PS: I am able to do the basics: cracking wep, arp poisoning with ettercap.......

Thank you.