Comment 2 for bug 790352

Thanks Patrick! Finally this bug is solved.

For you who didn't follow:
Open /usr/share/net-responsibility/lib/options.rb as root to edit. Find this line:
IO.popen("ifconfig -a | grep HWaddr | cut -c39-") do |mac_addr|

Replace it with this line:
IO.popen("LC_ALL=en_EN ifconfig -a | grep HWaddr | cut -c39-") do |mac_addr|

That should do the trick.