According to the official website, the software is used to remove the DRM from M4V to MP4 files. It's possible that the codecs used in the files are not possible to be decoded by the SmartTV. As far as I know, SmartTVs should play MP4 files natively, but if that doesn't happen, convert them to another format like AVI or MPEG. These two formats are universally available for almost any device released.
You can choose a video format from the following list: http://software.informer.com/search/video+converter