Ok, it took me a little while, but I think I've got some of this figured out.
The function you are using ("Depth_ImGui_AddAudioFile_Voice") deals with voice sound sources, but the files you are specifying ("00_03_apartment1/amb/object/radio_show/music/radio_song_"+i) is a soundbank sound source instead. Soundbanks are used for sounds that do stuff like ambient noises or sound effects, but voice sounds are used for dialogue. The two aren't interchangeable, i.e. you can't use a soundbank file in a function designed for a voice file or vice versa.
If you want to play this music in some kind of a jukebox sense, you would need to use the Sound_CreateAtEntity/Sound_Play functions. I put together a
page on the wiki regarding playing audio so you can figure out how exactly you want it all put together.