Software-properties: remove file lsb-release (as root) :
rm -f /etc/lsb-release
It's a small bug, I posted it on our forum 2 or 3 times already.
Then it should start working.
Most of the gnome packages has been removed before. Honestly I never installed them in any Sparky version.
So... don't follow the instruction from the external forum, becouse we don't use gnome.
Sparky Mate Edition has a few packages around gnome preinstalled such as network-manager-gnome, camorama, gnome-alsamixer, gnome-icons, gufw, gdebi, liferea, simple-scan, system-config-printer.
Keep all of them as well as zenity zenity-common libreoffice-gtk.
You can remove packs: metacity metacity-common (if is still there)
sudo apt-get remove metacity metacity-common
Anyway i will try to report the bug on mate forum, becouse it's nothigh about Sparky.