My Dear Friend Add All these NameSpaces.....
using System;
using System.Collections;
using System.Configuration;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Data;
using System.Xml.Linq;
using CrystalDecisions.CrystalReports.Engine;
using CrystalDecisions.Shared;
using System.Data.SqlClient;
Ok, This will be helpful to you