React Basics: Decomposing our Application Uncaught ReferenceError: Player is not defined

function Header(props){
  return (
    <div className="header">
      <h1>{props.title}</h1>
    </div>
  );
}

Header.propTypes = {
  title: React.PropTypes.string.isRequired, 
};

function Application(props) {
  return (
    <div className="player">
      <div className="player-name">
        {props.name}
      </div>
      <div className="player-score">
        <div className="counter">
          <button className="counter-action decrement"> - </button>
          <div className="counter-score"> {props.score} </div>
          <button className="counter-action increment"> + </button>
        </div>
      </div>
    </div>
  );
}

Player.propTypes = {
  name: React.PropTypes.string.isRequired,
  score: React.PropTypes.number.isRequired,
};

function Application(props) {
  return (
    <div className="scoreboard">
      <Header title={props.title} />

      <div className="players">
        <Player name="Jim Hoskins" score={31} />
        <Player name="Andrew Chalkley" score={33} />    
      </div>
    </div>
  );
}

Application.propTypes = {
  title: React.PropTypes.string, 
};

Application.defaultProps = {
  title: "Scoreboard",
}

ReactDOM.render(<Application />, document.getElementById('container'));
```Javascript

However, unlike the video, this code is not working...
and I'm getting this error code.

app.jsx:31 Uncaught ReferenceError: Player is not defined
    at eval (eval at transform.run (babel-browser.min.js:4), <anonymous>:57:1)
    at Function.transform.run (babel-browser.min.js:4)
    at exec (babel-browser.min.js:4)
    at babel-browser.min.js:4
    at XMLHttpRequest.xhr.onreadystatechange (babel-browser.min.js:4)
(anonymous) @ app.jsx:31
transform.run @ babel-browser.min.js:4
exec @ babel-browser.min.js:4
(anonymous) @ babel-browser.min.js:4
xhr.onreadystatechange @ babel-browser.min.js:4
XMLHttpRequest.send (async)
transform.load @ babel-browser.min.js:4
run @ babel-browser.min.js:4
runScripts @ babel-browser.min.js:4

Can anyone please help?

...  Am I the only one who can hardly make progress in React Track?