DHCP not working with "Too few arguments" error log

This thread says it shall be possible: Pi-hole running on Openhabian? - Installation - openHAB Community that's why I tried it.

OpenHABianPi is based on Debian Jessie (I think the same as the raspbian distribution). Documentation is here: openHABian | openHAB
This should come without special configuration for dnsmasq because out of the box it is configured as DHCP client.

What do you mean by "where we can see how the Pi-hole package is installed"? I used the piping to bash method described here GitHub - pi-hole/pi-hole: A black hole for Internet advertisements to install it manually