An Error with I-Doser Prenium?

[Mats1107]

Good day. So i was going to try out another dose, and i like the backround music feature in I-Doser. So i put one of my own music tracks in the folder and it played out perfectly. Then i put in another of my own music tracks in the folder, BUT THIS TIME i could only hear the dose sound and not the music. This has happend with several other of my own music tracks as well. So of course i wonder; What is the reason for this? How can i fix it?

Thank you for any advice!