I managed to download the only version of this application and installed it. Opened an MP3 file and checked its functionality and everything works as described, but there are no saving features. This means you won't have the possibility to save the opened file after it's processed for Karaoke singing.
You can try tools like Audacity to remove the vocals for a track and then save the resulted track.
Download Audacity: http://audacityteam.org/