Right, I finally got it to work.
Things suggested in this thread did not work for me(editing prefs.js).
I found this:
http://bugs.gentoo.org/show_bug.cgi?for ... &id=219444
It seems that when the protocol-handler for http/https is not set in thunderbird, it uses gnome defaults, so what is configured using gconf-tool and friends. That is wrong by default as well apparently, I got the 'Couldn't load XRE functions.' error. Running the following two commands from a terminal fixed it:
Code: Select all
gconftool-2 --set /desktop/gnome/url-handlers/http/command -t string 'firefox %s'
gconftool-2 --set /desktop/gnome/url-handlers/https/command -t string 'firefox %s'
It was set to /usr/lib/mozilla-firefox/firefox which produces the error.
Thanks for the help tutaepaki!