object reference not set to an instance of an object

CONSTANT
-----------
namespace InternationalLaundry
{
    public class Constant
    {
        // SELECT AND EMPTY VALUE
        public static string EMPTY_LIST_ITEM = " ---Select--- ";
        public static string EMPTY_LIST_ITEM_VALUE = "0";

        public static string laundry_db = "InternationalLaundry.Properties.Settings.InternationallaundryConnectionString";
    }
}


CLASS LIBRARY
----------------     
   public Database db;

        public CustomerDataManagement(string csstring)
        {
            db = DatabaseFactory.CreateDatabase(csstring);
        }
        
 //VIEW CUSTOMER REPORT
 private const string USP_Get_Customer_Data = "USP_Get_Customer_Data";  


//VIEW CUSTOMER REPORT
        public DataSet SELECT()
        {
            try
            {
                DbCommand com = db.GetStoredProcCommand(USP_Get_Customer_Data);
                return db.ExecuteDataSet(com);
            }
            catch (Exception)
            {
                throw;
            }
        
        }

PRESENTATION LAYER
------------------------

using Ilc = CustomerManagement;

   public partial class CustomerApplication : Form
    {

        public Ilc.CustomerDataManagement obj;
     

        public CustomerApplication()
        {      
            InitializeComponent();
            Binddata();
        }
   private void CustomerApplication_Load(object sender, EventArgs e)
        {       
            obj = new CustomerManagement.CustomerDataManagement(Constant.laundry_db);

        }
        private void Binddata()
        {
          
                DataSet dsCustomers;                         ---------->PROBLEM
                dsCustomers = obj.SELECT();
                this.dataGridView1.DataSource = dsCustomers.Tables[0];
               
        }