Playlist problems: Rocket Player and Music Player. Power Amp is Fine

Initially, I took my pc based MP3 collection and moved it to an external SD card on my Samsung S3. Using Poweramp, I imported the playlists and everything worked perfectly. Since then I have tried a variety of different players none of which posed any problems with any of the existing playlists. In other words, all players I used saw the same playlists/songs as Poweramp did.

Recently, I re-ripped my CD collection using a better format, using PC iTunes I built playlists with the new files and used iSynch to move them to my phone. Perfect so far... All old and new playlists were correctly populated with the old/new songs and each worked in all players. Then I made a change on my PC, re-synched my phone and now all the OLD playlists are empty for all players except Poweramp. The other players still have the NEW playlists correctly populated but the OLD list contain zero files.

Any ideas on how I can get these old playlists re-populated for ALL the players? AV Controller by Yamaha is one of these players giving me problems. The goal is make this my primary player as it allows me to stream audio from my phone directly to my AV Amp.