Ok, maybe need some more info here to be able to troubleshoot. 1) Faircrack 0.3 worked perfectly. 2) You made back-up copies of the original files that 0.41 replaces. 3) You have all 7 of the new files on your system in the FAS directory (check with ls -al, dates of the new files should not be older than 25th May 2011).