I tried to install cinnamon on my Kubuntu 13.10, just upgraded from 13.04 without problems.

There is this ppa:
ppa:gwendal-lebihan-dev/cinnamon-stable

Also tried to use the non-ppa-versions (those shipped with *Ubuntu).

I get the error message from within lightdm:

Unable to load session 'cinnamon'

or

Unable to load session 'cinnamon2d'

I also deleted my gnome settings (all files/folders from my home dir) and reset cinnamon by using this command line:

gsettings reset-recursively org.cinnamon

Both didn't help. How do I get Cinnamon up and running? I'm fine with debugging. Would it be possible I did not upgrade my amd graphics driver properly?

Thanks in advance!
Ben

PS: My primary desktop is KDE, so I have no problems with unity not running - it isn't running anyway.