Can't play itunes music through mediamonkey

[Rico17]

I downloaded itunes on my new computer and then mediamonkey so that I can ditch itunes forever but I can't get the music to play. Media monkey says I need to add on QuickTime player because it does not support my itunes music files. I downloaded it and the sound doesn't come through now. Only on certain tracks. I'm really confused on why this is? Need help please.