if you can get the patched injection drivers working....
You could try using aircrack-ptw. Make sure you dont collect ivs though with airodump, use the cap file instead, so ya dont use the --ivs.. Its quicker by far and you can crack wep with around 20k collected packets.
Ya Airodump command is fine.
When i did use the old aircrack-ng, i used
aircrack-ng -f 2 -a 1 -b APmac -n 64 (filelocationname).ivs Can switch 64 for 128 too.
-f is the fudge factor, can try up to 4. If still no luck try disabling the korek attack by adding -k (from 1-17).
Still, now aircrack-ptw is out now, no need for that really
(Still trying to get injection working on cacko using the 2.418 kernel
hope that helps