@duub ,
1st of all check installation log re why /etc/skel/set_once.sh failed.
The skel directory contains the setup files. So if you have nothing to lose:
cd
cp -r /etc/skel/.config .
cp -r /etc/skel/.local .
cp /etc/skel/.gtkrc-2.0 .
and so on until you have problems
and restart i3