Thread: Pls Help me. i have error "CANNOT FIND SYMBOL"in java.THANKS A LOTzzzz in Advance

coding:
import java.io.*;
public class DHMain extends javax.swing.JFrame
{    
    /** Creates new form DHMain */
 
	public DHMain() 
   {
        initComponents();
        //jDesktopPane1.add( new DHFrame());
        java.awt.Dimension dim = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
        setSize(610,455);
        setResizable(false);
    } 
 
    /** This method is called from within the constructor to     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
 
    private void initComponents() 
     {
	//GEN-BEGIN:initComponents
 
	jdp = new javax.swing.JDesktopPane();
        jMenuBar1 = new javax.swing.JMenuBar();
        fileMenu = new javax.swing.JMenu();
	fileMenu1 = new javax.swing.JMenu();
        embedMenu = new javax.swing.JMenuItem();
        extractmenu = new javax.swing.JMenuItem();
        exitmenu = new javax.swing.JMenuItem();
	aboutMenu = new javax.swing.JMenuItem();
        piclabel=new javax.swing.JLabel(new javax.swing.ImageIcon("new2.jpg"));
	piclabel.setBounds(0,0,600,400);
	add(piclabel);
	setTitle("IMAGE-Stego");
        addWindowListener(new java.awt.event.WindowAdapter() 
	{
            public void windowClosing(java.awt.event.WindowEvent evt) {
                exitForm(evt);
            }
        });
        getContentPane().add(jdp, java.awt.BorderLayout.CENTER);
 
        fileMenu.setMnemonic('F');
        fileMenu.setText("File");
	fileMenu1.setMnemonic('h');
	fileMenu1.setText("Help");
        embedMenu.setMnemonic('m');
        embedMenu.setText("Embed");
        embedMenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                embedMenuActionPerformed(evt);
            }
        });
        fileMenu.add(embedMenu);
        extractmenu.setMnemonic('t');
        extractmenu.setText("Extract");
        extractmenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                extractmenuActionPerformed(evt);
            }
        });
 
        fileMenu.add(extractmenu);
        exitmenu.setMnemonic('x');
        exitmenu.setText("Exit");
        exitmenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
            exitmenuActionPerformed(evt);
            }
        });
	fileMenu1.add(aboutMenu);
        aboutMenu.setMnemonic('a');
        aboutMenu.setText("About");
        aboutMenu.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
            aboutMenuActionPerformed(evt);
            }
        });
        fileMenu.add(exitmenu);
        fileMenu1.add(aboutMenu);
	jMenuBar1.add(fileMenu);
	jMenuBar1.add(fileMenu1);
 
        setJMenuBar(jMenuBar1);
        pack();
    }	
 
 
  private void exitmenuActionPerformed(java.awt.event.ActionEvent evt) 
   {
 
	  System.exit(0);
    }
 
    private void extractmenuActionPerformed(java.awt.event.ActionEvent evt) 
  {    
        piclabel.setVisible(false);
        WizardFrame wf = new ExtractAction(this).getWizardFrame();
       jdp.add(wf);
     wf.moveToFront();
    }
    private void embedMenuActionPerformed(java.awt.event.ActionEvent evt) 
  {
 
     System.out.println("Embed Action Selected..");
 
	piclabel.setVisible(false);
        WizardFrame wf = new EmbedAction(this).getWizardFrame();
        jdp.add(wf);
        wf.moveToFront();
    }
 
    private void aboutMenuActionPerformed(java.awt.event.ActionEvent evt) 
  {
  javax.swing.JOptionPane.showMessageDialog(this,"TEXT HIDING IN IMAGE USING STEGNOGRAPHY\n\n"+"Created by : IT","About",javax.swing.JOptionPane.PLAIN_MESSAGE); 
    }	
    private void exitForm(java.awt.event.WindowEvent evt) {
 
        System.exit(0);
 
    }
 
      public static void main(String args[])
	 {
           new DHMain().show();
            }
 
    // Variables declaration - do not modify//GEN-BEGIN:variables
    private javax.swing.JMenuItem exitmenu;
    private javax.swing.JMenu fileMenu;
    private javax.swing.JMenu fileMenu1;
    private javax.swing.JDesktopPane jdp;
    private javax.swing.JMenuItem extractmenu;
    private javax.swing.JMenuItem embedMenu;
    private javax.swing.JMenuItem aboutMenu;
    private javax.swing.JMenuBar jMenuBar1;
    public javax.swing.JLabel piclabel;
    // End of variables declaration//GEN-END:variables
 
}

ERRORS:
C:\JavaPrograms>javac DHMain.java
DHMain.java:99: error: cannot find symbol
WizardFrame wf = new ExtractAction(this).getWizardFrame();
^
symbol: class WizardFrame
location: class DHMain
DHMain.java:99: error: cannot find symbol
WizardFrame wf = new ExtractAction(this).getWizardFrame();
^
symbol: class ExtractAction
location: class DHMain
DHMain.java:109: error: cannot find symbol
WizardFrame wf = new EmbedAction(this).getWizardFrame();
^
symbol: class WizardFrame
location: class DHMain
DHMain.java:109: error: cannot find symbol
WizardFrame wf = new EmbedAction(this).getWizardFrame();
^
symbol: class EmbedAction
location: class DHMain
Note: DHMain.java uses or overrides a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
4 errors

cannot find symbol WizardFrame

Where is WizardFrame defined? The compiler can not find its definition.

What is that class used for? Why is it used in the code? Is it defined in some package that you need to import?