Adicionar jpanel a um jpanel que esta numa jframe

Assuntos Gerais
#1

tenho uma jframe o que quero fazer é quando clicar num botao ela carrega um class que é uma jpanel para uma jpanel

codigo para adicionar o jpanel

[code]
public class adduser extends javax.swing.JPanel {

/** Creates new form adduser */
public adduser() {
    initComponents();
}

/** 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.
 */
@SuppressWarnings("unchecked")
// <editor-fold defaultstate="collapsed" desc="Generated Code">
private void initComponents() {

    jLabel1 = new javax.swing.JLabel();

    org.jdesktop.application.ResourceMap resourceMap = org.jdesktop.application.Application.getInstance(pombalingua.PombalinguaApp.class).getContext().getResourceMap(adduser.class);
    setBackground(resourceMap.getColor("Form.background")); // NOI18N
    setName("Form"); // NOI18N

    jLabel1.setText(resourceMap.getString("jLabel1.text")); // NOI18N
    jLabel1.setName("jLabel1"); // NOI18N

    javax.swing.GroupLayout layout = new javax.swing.GroupLayout(this);
    this.setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(39, 39, 39)
            .addComponent(jLabel1)
            .addContainerGap(337, Short.MAX_VALUE))
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
        .addGroup(layout.createSequentialGroup()
            .addGap(23, 23, 23)
            .addComponent(jLabel1)
            .addContainerGap(262, Short.MAX_VALUE))
    );
}// </editor-fold>


// Variables declaration - do not modify
private javax.swing.JLabel jLabel1;
// End of variables declaration

}[/code]

o que estou a fazer mal??

#2