I get this:

Setting up fr24feed (1.0.19-15) ...
You don't seem to have any dump1090 installed. On the fr24feed start it will automatically install dump1090-mutability.
useradd: user 'fr24' already exists
/var/lib/dpkg/info/fr24feed.postinst: 37: /var/lib/dpkg/info/fr24feed.postinst: systemctl: not found
/var/lib/dpkg/info/fr24feed.postinst: 42: /var/lib/dpkg/info/fr24feed.postinst: setcap: not found
/var/lib/dpkg/info/fr24feed.postinst: 57: /var/lib/dpkg/info/fr24feed.postinst: systemctl: not found
dpkg: error processing fr24feed (--configure):
subprocess installed post-installation script returned error exit status 127
E: Sub-process /usr/bin/dpkg returned an error code (1)
What I am doing wrong?