A very weird loader problem

programming flash
1

So i am trying to insert a sound inside a class of my game. In the constructor function i declare the variable

private var retDamage3:Sound = new Sound();

and in the place i want it to play i put this code

retDamage3.load(new URLRequest(“sfx/destruirbarra.mp3”));
retDamage3.play();

Except it gives the error:

Call to a possibly undefined URLRequest.

Any ideas?