Disable LW's media player. Then see this:
Setting Default video app but instead apply it to your audio app. You want to rip into rm files so nobody can play the files unless they have realplayer & can't burn them unless they have the full version of RP. Well I know lots of people who won't touch rm files, me being one of them. IMHO I think they're a waste of time. It's a patented format that only companies that pay RP a fee are allowed to include any type of RM playback codec or converter.