I have ever had this condition when upgrading Ubuntu Lucid to Ubuntu Maverick. (never happen when I use Backtrack). This condition happen because, there are still some bugs in Maverick. So we have to patch it first.
Using this command:
sudo airmon-ng start wlan0 [channel]
changing the channel from 1 to 10. Always ends up on fixed channel mon0: -1. So, i can’t do the injection. Being frustrated, I asked from forum to forum to find the solution. But still, no one knows how to solve the problem. Until I joined French Forum (with my limited capability of speaking French :lol). I found this solution below.
Here are the commands:
tar -jxf compat-wireless-2010-10-16.tar.bz2
patch -p1 < mac80211.compat08082009.wl_frag+ack_v1.patch
patch ./net/wireless/chan.c channel-negative-one-maxim.patch
#*** FIND LINE 13: KLIB=/lib/modules/2.6.31-wl/build
#*** REPLACE WITH: KLIB=/lib/modules/$(uname -r)/build
sudo make install
sudo make unload
sudo modprobe iwl3945
Because my wlan card interface is Intel Wireless Pro A/B/G 3945, so that what i typed after modprobe. If you are not sure and don’t know the interface you have, alternatively, you can change
sudo modprobe [interface] ---> sudo reboot
good luck guys… :)