method works great!

some tips:
the "station" is not used at all.
copy paste the required parameters into a notepad or something like leafpad and copy paste when requested (this will avoid mistakes)
you need to run 3 commands the second command finish in 10 seconds so it is normal.
your key will be something like xx:xx:xx:xx:xx so simply remove the : to get the key.
u will get 2 cap files wep-xx and reply-xx... u need the wep-xx.cap
the cap file might be in the same folder u run the commands on and not the root.
leave it for at least 40 mins to collect packets, am not a pro and seriously i don't know what are those readings so just leave it for sometime, my first trial failed coz i gave it 15 mins only.
use it during busy time of the day, don't wait till the end of midnight where no people r using, remember this method is based on packet sniffing.
your n900 will heat up so be careful and use battery cable as it will drain battery in less than an hour.
start testing on your own secured WEP router first, when it works the first time you will gain confidence

good luck n900s! say thanks