Ok, old thread... but first let me say thank you buecky for the answer. It was a reminder to look at the s1mp3-page for updates...
I have the players still here by me. One is defective, one is in working condition.
I found them this evening again and I tried again to make a backup with the tool "s1clone". Unfortunatelly the s1clone wizard won't finish the read-out, it terminates with error message: Das Zeitlimit für die Semaphore wurde erreicht".
Good try, but the problem still persists...