Question about online guide code for video player

Hello, I'm new to flash and I'm trying to make a video player following this guide http://www.photoshopcafe.com/tutorials/flash/videoplayer/videoPlayer.htm. By the end though, my code doesn't seem to like what they have there.

Here's my code:

btn1.addEventListener(MouseEvent.CLICK, vid1);

btn2.addEventListener(MouseEvent.CLICK, vid2);

btn3.addEventListener(MouseEvent.CLICK, vid3);

btn4.addEventListener(MouseEvent.CLICK, vid4);

function vid1(e:Event):void{

vidPlayer.source = "Shephard.flv"

};

function vid2(e:Event):void{

vidPlayer.source = "Austen.flv"

};

function vid3(e:Event):void{

vidPlayer.source = "LaFleur.flv"

};

function vid4(e:Event):void{

vidPlayer.source = "John.flv"

};

And here's what it yells at me:

I have the videos in the same folder like it says and they're flv just like the example - the only thing I changed are that there are 4 buttons and videos now. Any idea what's wrong?

Thanks a bunch for your time,

Arnold