Apple Media Tool 2.0: Use Wave File for Ambient Sounds
In Apple Media Tool 2.0, ambient sounds don't seem to work with SND files; I get a "end of file -39" error. The sound itself is fine, and plays in other screens, and in the preview. If I substitute a WAVE sound, then it works fine.
Using SND files as ambient sounds in AMT 2.0 does not work correctly. Apple is testing and investigating this behavior. Until a fix is available, WAVE files should be used as ambient sounds.