Ok, so there was a bit of a saga with libnfs and Windows leading up to the release of XBMC Gotham. Major issues with libnfs meant that your entire library could get dropped by XBMC when running 'clean library' due to, basically, stale sockets.
You can read about it in painful detail in that thread, but suffice it to say eventually XBMC developer Memphiz and I found a fix.
It's really a two part fix - one part XBMC code, fixed in Gotham beta 4 and on, and one part a fix in libnfs itself. The libnfs fix does not seem essential, and has not actually made it in to XBMC Gotham.
In theory, errors might just occasionally occur with XBMC (resulting in files being dropped from your library), when using specifically Windows and NFS, and to that end here is a replacement libnfs.dll that I personally recommend you but in your
C:\WHERE_YOU_PUT_IT\Gotham\XBMC\system
..folder.
Replacement libnfs.dll for XBMC Gotham on Windows
