It was working when running firefox-4.0 from ubuntu-mozilla-daily/ppa which has the betas and nightlies, and quit working with mozillateam /firefox-stable which has the final firefox 4. This is because the language packs are in /usr/lib/firefox-addons/extensions/ and not /usr/lib/firefox-4.0-addons/extensions/ .
Here is a workaround: `firefox -uilocale en`, go to the addons manager, open the language pack pane, disable language packs. I filed a bug over there: https://bugzilla.mozilla.org/show_bug.cgi?id=644933 ** Bug watch added: Mozilla Bugzilla #644933 https://bugzilla.mozilla.org/show_bug.cgi?id=644933 ** Also affects: firefox via https://bugzilla.mozilla.org/show_bug.cgi?id=644933 Importance: Unknown Status: Unknown -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/677815 Title: Firefox crashes with XML Parsing Error -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs