Error when running DTS package from code

  // Name of the package to run
             string packageName = "Backup";
             object pVarPersistStgOfHost = null;

             DTS.PackageClass package = new DTS.PackageClass();
             package.LoadFromSQLServer("localhost", "sa", "sa", DTS.DTSSQLServerStorageFlags.DTSSQLStgFlag_UseTrustedConnection
             , null, null, null, packageName, ref pVarPersistStgOfHost);

             try
             {
                 // Execute the package
                 Console.WriteLine("DTS Package Executing..");
                 package.Execute();
                 Console.WriteLine("DTS Package Completed");

             }
             catch (Exception ex)
             {
                 Console.WriteLine(ex.Message);
             }

             finally
             {
                 package.UnInitialize();
                 package = null;
             }