Sorry, i away for some time due to work.
If i remember correctly, what happen was, when i load my sound, the .m4a wasn't generated, because i am using Windows XP (i think win 7 is required for conversion). So when i play it on the browser it works fine, because it is reading the .ogg files. but when i load it to Cocoon JS, it failed to find the .m4a and crash.
So, you need to have both .m4a and .ogg for each of sound. and for the 7 little animal sounds, i do not have any problem as i have more than 7 sounds. but i do not preload any of them.