Either "network is down" or "device or resource busy"

Hi there,

I have problems with my WiFi hardware. I am on Debian Linux 3.16 on a host (not a virtual machine) and my external WiFi card is Alfa AWUS036H.

The problem is the following:
[code]# aireplay-ng --deauth 0 -a $BSSID mon0
10:40:37  Waiting for b...