
I do not recommend Real Player which is way too bloated and as a result can cause issues. Instead I'd use the much leaner VLC which is the world's most popular free open-source player, and can play those file types.
When you install VLC if you don't want it to be your default player because you prefer Windows Media Player or another, just install it at all defaults and it will pick up the file types that others cannot play including this one.
After installing VLC you can try opening those files to see if it opens on it's own to play them. If not then go into VLC and choose Open from the File tab to browse to and open the Real Jukebox files.
Keep me posted on your progress as I will be here to help until the case is resolved.