Playing video from HD on TV

I have a LCD flat panel connected to a DirecTV Cinema Connection Kit. I'd like to back up my 550+ DVDs to my 3TB NAS and play them from there. I've loaded TVersity on the PC.
When I tried to play a movie I received an error message the files cannot be played.
What needs to be done to play these videos? I couldn't find an answering when searching the forums.