You are my Man!
Now it works!
Thank you very much.
Will try later if its fine still after a restart.
LibreELEC:~ # export PATH=$PATH:/storage/.kodi/addons/service.system.docker/bin
LibreELEC:~ # echo $PATH
LibreELEC:~ # docker -v
Docker version 1.13.1, build 1.13.1
If you didn't restart since installing, that may have been the issue.
i did restart since installing.
Now after the restart, same Issue. Maybe i try to install LibreElec completely new.