Random() problem

why does the debug give me this error below??

1180: Call to a possibly undefined method random.

This is the code here:

var myArray = new Array();
var skipped;
var rand:Number;

myArray[0] = “100”;
myArray[1] = “200”;
myArray[2] = “300”;
myArray[3] = “400”;

if(skipped!=true)
{
rand = random(4);
skipped=true;
gotoAndPlay(myArray[rand]);
}

what i want to do is load a number from the array!!