I had to reinstall kde plasma desktop, and somehow at the end, got this error:

could not perform immediate configuration on phonon-backend-vlc. It referred to a man page that was less than useful.

At the end it seemed that it was some kind of “protection” which is triggered on huge installs.

So I figured out that I had to install the offending package by itself. I located the package in the cache and did this:

dpkg -i /var/cache/apt/archives/phonon-backend-vlc_0.6.0-1_i386.deb

Upon which it spurted out dependency issues. So:

apt-get -f install phonon-backend-vlc

which seemed to work.

Then I continued the failed installation:

apt-get -y install kde-plasma-desktop