GUI: Start Applet Not Initialized

Question

My code is fine, it compiles just fine, my teacher looked at it and we cannot figure out how to make the applet run correctly. I am making a GUI that takes your weight and calculates how much you would weigh on a selected planet. When I run it, the applet pops up, but is blank and says "Start applet not initialised". I am using BlueJ. Here is my code:

   import java.applet.Applet;
   import java.awt.*;
   import java.awt.event.*;
   import java.util.Scanner;
   import javax.swing.JOptionPane;
   import java.text.*;
   public class Lab24 extends Applet implements ActionListener, ItemListener
{
private Label lab1;
protected TextField info, result;
private TextField input;
private Button butt;
private Choice planet;
private Font font1,font2,font3,font4;
static double w1,w2;

public void init(){
    setBackground(new Color(0,0,199));
    setLayout(new GridLayout(3,2,20,50));
    font1 = new Font("Courier",Font.PLAIN,15);
    font2 = new Font("Monospaced",Font.BOLD,8);
    font3 = new Font("TimesNewRoman",Font.PLAIN,12);
    font4 = new Font("Serif",Font.ITALIC,18);

    info.setText("This program allows you to\ncalculate your weight on\nanother planet!");
    info.setEditable(false);
    info.setFont(font1);
    add(info);

    lab1 = new Label();
    lab1.setFont(font2);
    lab1.setForeground(Color.black);
    lab1.setText("Enter your weight(in pounds)!");
    add(lab1);

    input = new TextField();
    input.addActionListener(this);
    add(input);

    planet.setFont(font3);
    planet = new Choice();
    planet.setBackground(new Color(107,180,243));
    planet.setForeground(Color.black);
    planet.add("Choose a planet");
    planet.add("Mercury");
    planet.add("Venus");
    planet.add("Mars");
    planet.add("Jupiter");
    planet.add("Saturn");
    planet.add("Uranus");
    planet.add("Neptune");
    planet.addItemListener(this);
    add(planet);

    butt.setFont(font2);
    butt = new Button("Calculate");
    butt.addActionListener(this);
    add(butt);

    result.setFont(font4);
    result = new TextField();
    result.setEditable(false);
    result.setForeground(Color.blue);
    add(result);
}

public void itemStateChanged(ItemEvent e) {
    if(e.getSource()==planet){
        switch(planet.getSelectedIndex()){
            case 1: w2 = w1 * 0.37;
            break;
            case 2: w2 = w1 * 0.88;
            break;
            case 3: w2 = w1 * 0.38;
            break;
            case 4: w2 = w1 * 2.64;
            break;
            case 5: w2 = w1 * 1.15;
            break;
            case 6: w2 = w1 * 1.15;
            break;
            case 7: w2 = w1 * 1.12;
            break;
        }
    }
}

public void actionPerformed(ActionEvent e) {
    if(e.getSource()==input){
        String s = input.getText();
        input.setText(s);
    }
    if(e.getSource() == butt){
        result.setText("You would weigh\n"+w2+" pounds!");
    }
}

public void paint(Graphics g){
    g.setColor(Color.red);
    g.drawOval(10,50,25,25);
}

}