I had this exact problem. I run El Cap. The CDLC was definitely in the correct folder and I bought Cherub Rock. All the CDLC showed up, I could select it and tune, and then it would just hang, the song not even starting. Turns out I WAS USING AN OUTDATED VERSION OF RSINJECTOR.APP. Once I searched these forums and downloaded the LATEST release, everything worked great! This is the step I would recommend to anyone having this particular problem.