I am reading what Garrett has just written and as far as I am aware I have not knowingly created a custom class. In going over the whole exercise I was reminded that "bounceSound" was not a class of the mp3 . It is correct - yes, the mp3 is imbedded in the library and, was exported for actionscript however, the mistake I made was in the "linkage" box of the sound properties. In the box labelled "class", I had loaded "bounceSound.mp3 ". What I did was remove the "mp3" from the file name so my class became "bounceSound". That is all I did and it works properly now so, my question now is - should the class be "bounceSound.mp3" or, "bounceSound" ? Was it an oversight of mine to include "mp3" in the class or, it should be there and the error is somewhere else. If you open the fla. I attached the other day and remove the "mp3" from the class name in the properties box, it will work.