Why isn't the audio playing for me?

[IMRSIV]

Running on Android...

on opencard
put specialFolderPath("engine") & "/Sounds/MSG_1.wav" into tFirstSound
mobilePlaySoundOnChannel tFirstSound, "current", "now"
put specialFolderPath("engine") & "/Sounds/MSG_2.wav" into tSecondSound
mobilePlaySoundOnChannel tSecondSound, "current", "next"
end opencard

The paths are correct and the files exist. Nothing plays at all, not the first or the second sound. If I remove the second "put" and the second "mobilePlaySoundOnChannel":

on opencard
put specialFolderPath("engine") & "/Sounds/MSG_1.wav" into tFirstSound
mobilePlaySoundOnChannel tFirstSound, "current", "now"
end opencard

then the first sound plays. What am I doing wrong?