im not to much of a wiz myself but the card is in monitor mode right? Im not sure if it will still catch ivs if it is not in monitor mode. to put your card in monitor mode run ifconfig -a to see all devices then pick yours in my case it was wifi0 and then type ifconfig start DEVICE then it will tell you wich one is in monitor mode mine ended up being ath1 was the selectedd one for monitor mode and i get ivs really fast using a similar attack script. try using -x 750 at the end of that command and see if that speeds it up any. From what i understand that will broadcast the messege 750 times a second but i may be wrong!!