jerko

hi, im trying to crackwpa2 psk and after i type the aireplay-ng -0 10 -a [bSSID here] -c [sTATION here] mon0 it will only receive like 6 ACKs at max and won't handshake. my signal is like 15-20 percent to this network, but Ive successfuly cracked wep networks with signal of this low strenght or lower, some of them work up to 2 mbits. whats the problem, why wont it handshake to this network? on youtube vid ive seen guy receiving 64 ACKs in just 5 tries, Ive tried 100 tries and it got only 6 ACKs. how to get more acks?