Record Mic using SampleDataEvent works only on some computers.

I made a swf that records your mic and allows you to play it back.  I load the soundBytes into a float and play the float back.  It works fine on the computer I developed it on (in IE, Chrome and Firefox) .  It does not work on my second laptop.  And a few people in some forums have said it is not working either.

Here is the file.  http://www.buttonbeats.com/images/MicCapture.html

Here is the code.  Do I need certain plugins besides the flash player?

micRec.addEventListener(MouseEvent.CLICK,recordMic);

function recordMic(event:MouseEvent){
micRec.x = -250;
stopRecord.x = 0;
const DELAY_LENGTH:int = 4000;

var mic:Microphone = Microphone.getMicrophone();
mic.setSilenceLevel(0, DELAY_LENGTH);
mic.gain = 80;
mic.rate = 40;

mic.addEventListener(SampleDataEvent.SAMPLE_DATA, micSampleDataHandler);

stopRecord.addEventListener(MouseEvent.CLICK,SREC);

var soundBytes:ByteArray = new ByteArray();

function micSampleDataHandler(event:SampleDataEvent):void
{
    while(event.data.bytesAvailable)
    {
        var sample:Number = event.data.readFloat();
        soundBytes.writeFloat(sample);
    }
}

function SREC(event:MouseEvent):void
{      

stopRecord.x = -250;

    mic.removeEventListener(SampleDataEvent.SAMPLE_DATA, micSampleDataHandler);
    soundBytes.position = 0;
    var sound:Sound = new Sound();
    sound.addEventListener(SampleDataEvent.SAMPLE_DATA, playbackSampleHandler);
soundPlay.addEventListener(MouseEvent.CLICK,SP1);
function SP1(event:MouseEvent){
  soundBytes.position = 0;
    sound.play();
}
}

function playbackSampleHandler(event:SampleDataEvent):void
{
    for (var i:int = 0; i < 8192 && soundBytes.bytesAvailable > 0; i++)
    {
        var sample:Number = soundBytes.readFloat();
        event.data.writeFloat(sample);
        event.data.writeFloat(sample);
    }
}
}