Just wanted to confirm with you that you have used our Linux Instructions to install RoonServer on this machine and that you have made sure to install the dependencies first (ffmpeg/libasound2/cifs-utils/glibc 2.14 or higher) .
Also, have you made sure to allow Roon past any firewalls you may have installed and that multicast is setup to properly pass through your linux firewall? This thread may be of help to ensure that the firewall is properly set up: (Android Roon Remote looses connection to Core (daily)).