ASP.NET Crystal Report 問題

using System;

using System.Collections;

using System.Configuration;

using System.Data;

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.Web.UI.WebControls.WebParts;

using System.Xml.Linq;

using CrystalDecisions.Shared;//水晶報表的引用

using CrystalDecisions.CrystalReports.Engine;//水晶報表的引用

using System.Data.SqlClient;

public partial class EvaluateReport : System.Web.UI.Page

{

    string connString = System.Configuration.ConfigurationManager.ConnectionStrings["henry"].ConnectionString;

    static string sql = "";

    private ReportDocument evaluateDocument;

    protected void Page_Load(object sender, EventArgs e)

    {  

        SqlConnection conn = new SqlConnection(connString);

        try

        {

            conn.Open();

        }

        catch (Exception ex)

        {

        } 

        string sql = "select * from evaluate left join class on evaluate.classid=class.classid left join course on          evaluate.courseid=course.courseid left join [week] on evaluate.weekid=[week].weekid left join [user] on evaluate.OperatorID=[user].recuid left join times on evaluate.timesid=times.timesid left join teacher on evaluate.teacherid=teacher.teacherid";

        SqlDataAdapter da = new SqlDataAdapter(sql, conn);

        DataSet ds = new DataSet();

        da.Fill(ds,"EvaluateList");

        evaluateDocument =new ReportDocument();

        string reportPath = Server.MapPath("report1.rpt");

        evaluateDocument.Load(reportPath);

        evaluateDocument.SetDataSource(ds);

        CrystalReportViewer1.ReportSource=evaluateDocument;           

    }

}

錯誤提示為

不知是為什麼？who can help me ?