Java Programming

Hi people, the following code has a problem, the

import org.jdesktop.layout.GroupLayout;

cannot be resolved, why? what does this mean? how can i fix the problem? thanks!

package gui;

import java.awt.Container;
import java.awt.EventQueue;
import javax.swing.JFrame;
import org.jdesktop.layout.GroupLayout;

public class Creditg extends JFrame
{

    public Creditg()
    {
        initComponents();
    }

    private void initComponents()
    {
        setDefaultCloseOperation(3);
        GroupLayout layout = new GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(layout.createParallelGroup(1).add(0, 400, 32767));
        layout.setVerticalGroup(layout.createParallelGroup(1).add(0, 300, 32767));
        pack();
    }

    public static void main(String args[])
    {
        EventQueue.invokeLater(new Runnable() {

            public void run()
            {
                (new Creditg()).setVisible(true);
            }

        });
    }
}