[Zubersoft]

Copy the missing audio files into the location MobileSheets is referencing them from. That location may be different between your phone and tablet (the phone may be storing the audio files in the storage location, and you have not deleted those files). You can see the file path by long pressing the song on the library screen to select it, tap Edit Song, go to the audio tab, and you'll see the file path below the audio track title.

Mike