Search the tape for hidden messages from the evil one. Play it backwards first.

Here is the source.

import java.awt.*;
import java.awt.event.*;
import java.applet.*;

public class play extends Applet {

    public void init () {
      Button b1=new Button("play backward");
      Button b2=new Button("play forward");
      add(b1);
      add(b2);
    }

    public boolean action(Event e, Object o) {
        if ( !(e.target instanceof Button) ) return false;
        if ( "play backward".equals((String)o) )
            play( getCodeBase(), "yenrab.au");
        else
            play( getCodeBase(), "barney.au");
        return true;
    }

}