I am following this guide trying to turn my Ubuntu-desktop-installation into Ubuntu-server.

However, I am having problems already in step 2. Using tasksel to remove/install anything returns with:

tasksel: aptitude failed (100)

I've Googled around and read this question (it was the first thing I tried), but nothing suggested works.

I am running 12.04.

Afraid I do now have much more information than that. If anyone could point me in the direction of an error-log that I could look into I can supply with further info, but I have not found anything of interest in them yet.