SMB to NFS - Poster.jpg not picked up

I've read that NFS is better than SMB and so decided to switch.

So to do this I:

- Set <importwatchedstate>true</importwatchedstate> in advancedsettings.xml
- Exported video library to seperate files
- Dropped the video and music mysql databases
- Deleted sources.xml
- Deleted thumbnails folder from central location (I use <pathsubstitution> in advancedsettings.xml to centralise thumbnails)
- Rebooted (mysql databases were recreated)
- Added sources back in
- Updated library

Now this is where the issue comes in. Poster.jpg is not being picked up and so I have no thumbnails showing. Fanart is being picked up correctly. If I bring up the context menu on a TV Show/Movie and do get thumb I can choose the local thumb and it displays fine and is cached in the central thumbnails directory as expected.

Obviously I don't want to have to manually do this for every Film/TV Show and any new content that is added.

Anyone know what the issue is?

Thanks

EDIT: Forgot to mention that I am using openelec 2.0 beta 4.

EDIT2: Don't know if this is relevant but I'm using Aeon Nox 3.0
Folder structure:

/Films/Filmname (year)/Filmname (year).mkv
Filmname (year)-fanart.jpg
Filmname (year).nfo
Filmname (year).tbn
logo.png
movie-trailer.mp4
poster.jpg

So I guess its not picking up the .tbn either?

Also when in file mode and browsing thumbnail is not shown either.

Figured this out! When I deleted the Thumbnails folder xbmc was not recreating the individual folders within the directory. I'm sure it used to do this?

Anyway I copied an empty directory structure into the thumbnails directory and it all started working!