i have been using aiff files and i am using media centre 25 now. just an update, i was with it closing unexpectly when access files via JRiver panel, what has now solved the problem for me is putting the library on an external drive and plugging it into the pi's USB (the drive is plugged into a usb extension cable with a dedicated power supply so it doesn't drain any power from the pi.). I then imported those files into jriver as opposed to from a network mapped drive from my NAS drive. So using the external drive files i get no problems with it crashing so my problem must have been something relating to accessing music from a mapped via jriver.