publickey error using cvs
It may be because scrotwm has been renamed to spectrwm and I'm guessing the old CVS repository has been removed.

As per the above link, you can clone the new git repository using either of the following:

    $ git clone git://opensource.conformal.com/spectrwm.git
    $ git clone https://opensource.conformal.com/git/spectrwm.git