I suppose that you could install the mfg/pro software on one server and the database on another but another question is where would you have the Progress software and how are you gonna connect the servers together? You could install the Progress Software on both servers but that would be an extra license.
You can't mount the DB server using NFS and then launch a Progress server against the DB as Progress doesn't support NFS connections (Progress article 20406). This is simply because a link like NFS can't be guaranteed and data integrity could be put at risk.
Also, if you have your installation split like the way you suggest, what about if one server goes down? It wouldn't be nice to have the database but no application software to run against it, or application software but no database!
HTH,
James.
