Error in exporting crystal report

i want to export crystal report to pdf i want to display i am getting error Invalid report file path. while exporting 
i am using this code 
 

protected void Button2_Click(object sender, EventArgs e)
    {
        string query;
        // string q = Request.QueryString["q"];         con.Open();
        query = "select * from Tech_data where id ='" + TextBox1.Text + "'";
        cmd = new SqlCommand(query, con);
        da = new SqlDataAdapter(cmd);
        dt.Clear();
        da.Fill(dt);
        if (dt.Rows.Count > 0)
        {
            cryRpt.Load(Server.MapPath("~/CrystalReport.rpt"));
            cryRpt.SetDataSource(dt);
            cryRpt.SetDatabaseLogon("sa", "123456789", @"TRAINING-ROOM-8", "Technical_sup");
            CrystalReportViewer1.ReportSource = cryRpt;
            CrystalReportViewer1.DataBind();
            CrystalReportViewer1.RefreshReport();
        }
        con.Close();
    }
    protected void btnShow_Click(object sender, EventArgs e)
    {
        ExportOptions CrExportOptions;
        DiskFileDestinationOptions CrDiskFileDestinationOptions = new DiskFileDestinationOptions();
        PdfRtfWordFormatOptions CrFormatTypeOptions = new PdfRtfWordFormatOptions();
        CrDiskFileDestinationOptions.DiskFileName = pdfFile;
        CrExportOptions = cryRpt.ExportOptions;    <<<--- ERROR
        CrExportOptions.ExportDestinationType = ExportDestinationType.DiskFile;
        CrExportOptions.ExportFormatType = ExportFormatType.PortableDocFormat;
        CrExportOptions.DestinationOptions = CrDiskFileDestinationOptions;
        CrExportOptions.FormatOptions = CrFormatTypeOptions;
        cryRpt.Export();
    }