The developers of Kiwix, an offline Wikipedia reader, had a problem in the .deb package of Kiwix 0.9 beta1, as delivered via Ubuntu's Personal Package Archive: Kiwix simply would not launch at all.
Emmanuel Engelhart, Kiwix developer, believes his team just fixed it (thanks to some troubleshooting they and I did at Wikimania).
Can someone on Ubuntu install Kiwix 0.9 beta2 via the Ubuntu PPA and verify that it launches? http://www.kiwix.org/index.php/Ubuntu_PPA has the directions -- ppa:kiwixteam/ppa is the repository, as you can see on https://launchpad.net/~kiwixteam/+archive/ppa .
(And if you're interested in testing Kiwix more thoroughly, you can join the Kiwix testers' mailing list at https://lists.sourceforge.net/lists/listinfo/kiwix-testing . Kiwix is cross-platform and needs testers on Windows, Macintosh & Linux.)