First off, I havn't done anything

I've compiled sourcecode sub made to a plugin you can install on linux/xbmcbuntu 32 bit.
What changes sub made to allow xbmc access I have no idea of, I'm not a programmer, but I try to help if I can

I guess it's just normal under the hood tweaks.
This is what I know/believe:
Currently there are 2 ways to access NPVR from inside XBMC.
1. Mvallevand plugin, this is a normal xbmc plugin that runs on current stable xbmc versions , it try to imitate NPVR client.
2. sub's plugin, this is a PVR plugin, for the upcomming pvr support in next xbmc version, it's a unified frontend pvr that can use several backends, it has some defined set of features, and you need a plugin to make xbmc be able to talk to the backend and translate xbmc features into backend features.
I have to go to bed now, but I can try to explain more detail later.