JDBC ODBC related problem

i WANT HELP RELATED TO JDBC CONNECTIVITY WITH MS ACCESS.. HERE IS MY FULL CODE... import java.awt.Container; import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.ItemListener; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import javax.swing.*; public abstract class New_Customer extends JFrame implements ActionListener,ItemListner { JTextField textFieldId; JTextField textFieldName; JTextField textFieldContactNo;
JLabel l1; JLabel l2; JLabel l3; JLabel l4; JLabel l5; JLabel l6;
JComboBox combo; ComboBox b = new ComboBox(); String course[] = {"Navakal","SandhyaKal","Pudhari","MidDay","Inqlab","BusinessLine","Mumbai Samachar","Gujraj Samachar","Karnatak Malla","Vartahar","PunyaNagari"};
JButton b1; JButton b2; PreparedStatement ps; Container c = getContentPane(); New_Customer() { super("Shree DattaDigambar Samarth"); setBounds(140,250,777,555); c.setLayout(null); textFieldId = new JTextField(); textFieldName = new JTextField(); textFieldContactNo = new JTextField(); l1 = new JLabel("New Customer Entry"); l2 = new JLabel("Building No"); l3 = new JLabel("Customer Name"); l4 = new JLabel("Contact No"); l5 = new JLabel("Paper");
combo = new JComboBox(course); l1.setBounds(10,10,340,20); l2.setBounds(10,20,140,70); l3.setBounds(110,20,140,70); l4.setBounds(300,50,140,20); l5.setBounds(400,50,140,20); textFieldId.setBounds(10,70,70,20); textFieldName.setBounds(110,70,180,20); textFieldContactNo.setBounds(300,70,90,20); combo.setBounds(400,70,130,20); b1 = new JButton("Add paper"); b2 = new JButton("Ok"); b1.setBounds(10,100,100,20); b2.setBounds(10,160,50,20);
c.add(combo);
c.add(b1); c.add(b2); c.add(l1); c.add(l2); c.add(l3); c.add(l4); c.add(l5); c.add(textFieldId); c.add(textFieldName); c.add(textFieldContactNo);
setVisible(true); setDefaultCloseOperation(EXITONCLOSE);
b1.addActionListener(this); b2.addActionListener(this); combo.addItemListener(null);

    }
    public void actionPerformed(ActionEvent ae)
    {
        if(ae.getSource()==b2)
        {
            try
            {
                Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
                Connection con;
                con = DriverManager.getConnection("jdbc:odbc:Digambar_Dalvi");
                ps=con.prepareStatement("insert into Customer(Building_No,Customer_Name,Contact_No,Paper_Name)values(?,?,?,?)");


            ps.setString(1,textFieldId.getText());
            ps.setString(2,textFieldName.getText());
            ps.setString(3,textFieldContactNo.getText());                           
            ERROR{                String str = (String)combo.getSelectedItem();
            ERROR           ps.setString(4,combo.getText());
            ERROR           //ps.setString(4,str.getText());
            ERROR           ps.executeUpdate();
                }
                con.close();  

            }
            catch(Exception ex)
        {
            System.out.println("Error 1:"+ex);
        }
        }
    }
    public static void main(String args[])
{

    New_Customer v = new New_Customer() {};



}

}

AS I SHOW IN CODE THE ERROR PART...... THE QUESTION N PROBLEM IS I WANT TO SELECTE PERTICULAR PAPER FROM COMBOBOX AND THOSE SELECTED PAPER TEXT I WANT TO PRINT IN MS ACESS DATABASE..MEANS FROM THAT I COME TO KNOW THAT WHICH CUSTOMER HAVING WHICH PAPER........... HELP ME PLZ THANKS IN ADVANCED