I can not open m4p files purchased on the Music Store with Amadeus, why?
With QuickTime 6.5.1 (the update coming with iTunes 4.5), Apple decided without prior notice to forbid third-party applications the access to m4p files. One workaround is to play the files in iTunes and to use Jack to record the output from iTunes. Another workaround is to burn the file on an Audio CD and to open it from there.