Deleting the files in de SYSTEM folder didn't solve a thing, but I do think the problem lies within the RoCoo/Micro SD card combination.
23 FLAC files (convert from WAV)
- Sandisk 2GB Ultra II -> Plays without problems, card is recognized in the player Player gives 522MB/19xxMB (don't know the precise number of GB shown)
- Samsung 32GB Class 10 -> gives problems, card is not recognized in the player. Player gives 0MB/0MB
Weird thing is the card worked before, with the same album on it.
What else to try? Blow my money on a Sandisk 32GB gamble?