Quicktime Home Movies and DVD's Not Added to Library - "server not powerful enough to convert video"

Hi I'm running Plex Media Server on My ReadyNAS. When I try to add some quicktime movies to my library in the Home Video folder, they do not show up. AVI's show up and play ok. I also see an error message saying server not powerful enough to convert video. I believe same issue with DVD's/VideoTS folders. Does the NAS app not have the capability to play these files? I was hoping to not have to use a computer anymore as the Plex server. Do I need to convert those quicktime files and video TS folders to another video file type? What file would be best? Thanks.