Jerz, why do you need to run ARM if you are running JRec?
Because even though I'm using jrec I still need an NFS server and I believe its purpose is to hand over the receiver.arf file when the receiver requests it. I *think* there are other ways to do that with linux or rioboot but just using ARM for nfs seems easiest.

This page describes the step for installing a rio driver for linux but the author is still waiting on a volunteer to write up docs for windows Rio installation: http://jreceiver.sourceforge.net/rio/jrec-install-rio.html

EDIT: Oh, and you can look here as well under the heading "Windows/Rioboot".