Sound: 2 code lines--1 error

Hello community, I’m trying my best to learn how sound works in flash cs3. But I can’t get past the simplest thing… getting an imported mp3 to play. This is my code:

var s:Sound= new Sound(“test1.mp3”);
s.play();

Flash isn’t playing the sound because of the following error: 1067: implicit coercion of a value of type String to an unrelated type flash.net:URLRequest

The library shows that “test1.mp3” is of type sound. But AS3 thinks that it is a string variable. Does someone know what I should do?