Notices

Try
1- restart n900
2- run in xterm sudo gainroot load the bleeding edge driv
3- airodump-ng wlan0 see all the networks and close the xterm
4-start de faircrack and see if is working now
for me is working

Ok now it's working. The key was "airodump-ng wlan0" command. Thanks.

I use Ubuntu and it's in the repos.

If you are on Window$ then just search QtDesigner in Google and it's the first link. You will also need pyuic4 to convert the GUI files to PyQt when you have edited them.

EDIT: You can also use QtDesigner from Easy Debian on the N900. What a wonderful device we all have here

I have been tinkering with it some more trying to get the deauthentication to work, sofar not very succesfully (sorry @Trine) (same old story, works in xterm but not properly through the program calls).

In the meantime I made some ui changes, that are attached in the archive below with all of my other changes upto now (Main.py, FAS.py readAP.sh getinfo.sh scan.sh getmacmanaged.sh getmacmonitor.sh). Details are given in the Main.py file.
1) Start Packet Capture button now only becomes active when an AP is selected.
2) Injection Enable/Disable buttons now toggle after first button press.
3) Selecting a key file now shows key (Get Key button functionality redundant).
4) Re-purposed Get Key button to Clear Key button.
5) All clear buttons (WEP / WPA / Key) now delete individual files rather than all the files.
6) Selecting WEP / WPA / Key tab now performs a refresh of the files (ie. Refresh Cap button redundant).
7) WEP and WPA Decrypt button only activate when a cap file has been selected.

As per usual, make a back-up copy of the files to be replaced, copy the archive to the FAS directory on your N900 and extract with in xterm in the FAS directory:

tar -xzvf faircrack0.41.tar.gz

Enjoy

This is quite possible and may just be a normal function of the program. The program will only pick up APs with WEP or WPA encryption, ie. you will not see any APs which are not encrypted, so the scan will not produce any visible results if there is only open networks around.

This is a known problem for which I posted a fix a few pages back.

The blank fields could also be due to the ssid being hidden.

Yep, and also due to wifi not being active as per one of my earlier posts. Anyway, I think the op managed to get it going, I just wanted to add some more knowledge to the possible causes for anybody else encountering this problem.

I followed the procedure into a wep cracking but the decryption password I get is too long. It has 24 numbers! My ivs are above 50000 so I guess it's something about john's decryption.

What do you mean too long?

Also, you are talking about IV's which are for WEP cracking, and John which is for WPA cracking. Are you sure you know what you are doing?

Yes my mistake. Aircrack is making the decryption of cap files.

I decrypted 2 cap files and both showed 313233343563738930313233 as the password.