Nope, they're using Microsoft Windows.
Check out the video at the first link on this page, which is a link to instructions on how to download the 160Mb BitTorrent-hosted video that demonstrates the exploitation of the Diebold software:
http://www.equalccw.com/voteprar.html
There's also a few screenshot-by-screenshot demos linked there too, plus interesting exceprts from the Diebold policy guides.
Thanks