@bakgat First look inside of /var/log You should see some files in there with the name fog_error_[version].log Errors from the installer are redirected to these files. Post the last few lines of those files (or the whole log). It’ll help with figuring out what’s going on.
The dhcp configuration file on CentOS 7 / Fedora it’s located at /etc/dhcp/dhcpd.conf
You might also try to install dhcp manually. on CentOS 7 and Fedora 19-21 you’d use yum install dhcp, on Fedora 22 and up it’s dnf install dhcp
You might also see what is written for start and end ranges inside of /opt/fog/.fogsettings if that file exists.