Comment 3 for bug 380246

More specific instructions:

Open a terminal (Applications -> Accessories -> Terminal). Then run the following commands:
sudo rm /var/lib/dpkg/info/vagalume.{postinst,prerm,postrm}
sudo apt-get remove --purge vagalume
sudo apt-get clean
sudo apt-get update

You may reinstall the package with this command:
sudo apt-get install vagalume

Please let us know if you have any trouble.