Hi Peter,
This will only work on NAS devices with a x64 CPU.
As I wrote in this Just installed Roon 1.2 on a Synology DS716+ NAS topic:
I have only tried it on a Synology, I just downloaded the package in the /tmp directory and decompressed it
tar xvjf RoonServer_linuxx64.tar.bz2
After that I just started the RoonServer manually by
cd RoonServer
sudo ./start.sh
and it seems to run on it.
This is of course not a permanent install (especially in the tmp directory) but it indicates that it is possible to do.