Plex Media Server

I have moved my usb exteal hard drives from my windows box to my ubuntu box, set up plex media server, have it all loaded and working, added my libraries, waited for them to scan down, now every movie or tv episode i try to watch i get a "sorry there was a problem playing this file" or if i try to look at the movie/tvshow info, i get a "media not found" error.

the libraries are visible and all the meta data seems to be downloaded (covers for movies and tv shows are show up on screen).

i thought it might have been a permissions thing but i have been playing with that and having no success even with a chmod 777.

the drives are still ntfs, is that my problem? or anyone else got any ideas?

many thanks