My /var/lib/dpkg/alternatives/xulrunner was empty.
So I did "sudo rm /var/lib/dpkg/alternatives/xulrunner"
then reinstalled xulrunner-1.9.1 (like: sudo apt-get install xulrunner-1.9.1 )
then ... purged xulrunner-1.9.1 ( sudo apt-get purge xulrunner-1.9.1 )
Now everything is fine
My /var/lib/ dpkg/alternativ es/xulrunner was empty.
So I did "sudo rm /var/lib/ dpkg/alternativ es/xulrunner"
then reinstalled xulrunner-1.9.1 (like: sudo apt-get install xulrunner-1.9.1 )
then ... purged xulrunner-1.9.1 ( sudo apt-get purge xulrunner-1.9.1 )
Now everything is fine