I've just begun adding sounds to my level but find many do not play upon relaunching the game. I've positioned them and adjusted the settings so they sound right, then I save and close. Next time I launch the game the sound objects are present but I have to go into the track list and re-select the sound to make it work again. I have at least two other sounds that are working correctly - birds and ocean - but I cannot figure out what is different from them.
If the files are not playing, try checking the formats... Apparently the game is a bit picky when it comes to audio formats. Try converting the files to .ogg, if they aren´t already. »Convertion tool«
Thanks for the response - I think it was the 'play on add' checkbox because all my sounds are behaving now with that turned on.