to try the reinyection with the ipw3945 you must load ipwraw-ng drivers


With the broadcom, you can try to do the reinyection in a shell. to do this you only must write in the command line:
aireplay-ng -3 -x 400 -b "ap mac" -h "your mac" <interface>
or try this other
aireplay-broadcom-ng -3 -x 400 -b "ap mac" -h "your mac" <interface>
I haven't got broadcom, for this reason I only can help with this

PD: Excuse me but my english it's too bad