สอบถามปัญหาคำสั่ง ASP.NET เกี่ยวกับการ import excel ติด error คะ

<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.Master" AutoEventWireup="true"
    CodeBehind="Import.aspx.cs" Inherits="BacklogMonitoring.ImportData" %>

<asp:Content ID="Content1" ContentPlaceHolderID="HeadContent1" runat="server">
<link href="/Styles/Style.css" rel="stylesheet" type="text/css" />
<link href="/CSS/smoothness/jquery-ui-1.10.0.custom.css" rel="stylesheet">
<script src="/js/jquery-1.9.0.js"></script>
<script src="/js/jquery-ui-1.10.0.custom.js"></script>
    <style type="text/css">
        .myButton
        {}
    </style>
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="MainContent1" runat="server">
<center>
                <img alt="" class="style1" src="images/Import.png" /><br />
                        <br />
                        <br />

                   <asp:FileUpload ID="FileUploadToServer1" runat="server" />
                     <br />
        
                <br />
&nbsp;<br />
                    <asp:Button ID="btnUpload" runat="server"  
                    Text="Import" OnClick="btnUpload_Click"  
                    Width="100px" />
                    <br />
                    <br />
                    <asp:Label ID="lblMsg" runat="server" Visible="false" 
                    style="color: #FF0000; font-weight: 700; font-size: small;"></asp:Label>
                    <br />
                    <br />
                    <asp:GridView ID="grvBatchUpload" runat="server" CellPadding="4" 
                    GridLines="None" ForeColor="#333333">
                        <AlternatingRowStyle BackColor="White"  />
                        <FooterStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
                        <HeaderStyle BackColor="#990000" Font-Bold="True" ForeColor="White" />
                        <PagerStyle BackColor="#FFCC66" ForeColor="#333333" HorizontalAlign="Center" />
                        <RowStyle BackColor="#FFFBD6" ForeColor="#333333" />
                        <SelectedRowStyle BackColor="#FFCC66" Font-Bold="True" ForeColor="Navy" />
                        <SortedAscendingCellStyle BackColor="#FDF5AC" />
                        <SortedAscendingHeaderStyle BackColor="#4D0000" />
                        <SortedDescendingCellStyle BackColor="#FCF6C0" />
                        <SortedDescendingHeaderStyle BackColor="#820000" />
                    </asp:GridView>
                    </center>
                    </br>
                    </br>
                    </br>
</asp:Content>

using System;
using System.Collections;
using System.Collections.Generic;
using System.Configuration;
using System.Data;
using System.Data.OleDb;
using System.IO;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using MySql.Data.MySqlClient;

namespace BacklogMonitoring
{
    public partial class Import : System.Web.UI.Page
    {
        String strConnString = ConfigurationManager.ConnectionStrings["OFPConnectionString"].ConnectionString;
        String strSQL;
        MySqlConnection objConn;
        MySqlCommand objCmd;
        //object obj;
        protected void Page_Load(object sender, EventArgs e)
        {

        }
        public void BindGridView()
        {
            string FilePath = ResolveUrl("~/Uploads/"); // Give Upload File Path
            string filename = string.Empty;
            if (FileUploadToServer1.HasFile) // Check FileControl has any file or not
            {
                try
                {
                    string[] allowdFile = { ".xls", ".xlsx" };
                    string FileExt = System.IO.Path.GetExtension(FileUploadToServer1.PostedFile.FileName).ToLower();// get extensions
                    bool isValidFile = allowdFile.Contains(FileExt);

                    // check if file is valid or not
                    if (!isValidFile)
                    {
                        lblMsg.Visible = true;
                        lblMsg.Style.Add("color", "red");
                        lblMsg.Text = "กรุณาเลือกไฟล์ Excel เท่านั้น !!!";
                    }
                    else
                    {
                        int FileSize = FileUploadToServer1.PostedFile.ContentLength; // get filesize
                        if (FileSize <= 1048576) //1048576 byte = 1MB
                        {
                            filename = Path.GetFileName(Server.MapPath(FileUploadToServer1.FileName));// get file name
                            FileUploadToServer1.SaveAs(Server.MapPath(FilePath) + filename); // save file to uploads folder
                            string filePath = Server.MapPath(FilePath) + filename;
                            string conStr = "";
                            if (FileExt == ".xls") // check for excel file type
                            {
                                conStr = ConfigurationManager.ConnectionStrings["Excel03ConString"].ConnectionString;
                            }
                            else if (FileExt == ".xlsx")
                            {
                                conStr = ConfigurationManager.ConnectionStrings["Excel07ConString"].ConnectionString;
                            }

                            conStr = String.Format(conStr, filePath, "Yes");
                            OleDbConnection con = new OleDbConnection(conStr);
                            OleDbCommand ExcelCommand = new OleDbCommand();
                            ExcelCommand.Connection = con;
                            con.Open();
                            DataTable ExcelDataSet = new DataTable();
                            ExcelDataSet = con.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
                            DataTable dt = new DataTable();
                            if (ExcelDataSet != null && ExcelDataSet.Rows.Count > 0)
                            {
                                string SheetName = ExcelDataSet.Rows[0]["TABLE_NAME"].ToString(); // get sheetname
                                ExcelCommand.CommandText = "SELECT * From [" + SheetName + "]";
                                OleDbDataAdapter ExcelAdapter = new OleDbDataAdapter(ExcelCommand);
                                ExcelAdapter.SelectCommand = ExcelCommand;
                                ExcelAdapter.Fill(dt);
                            }
                            con.Close();
                            if (dt != null && dt.Rows.Count > 0) // Check if File is Blank or not
                            {
                                grvBatchUpload.DataSource = dt;
                                grvBatchUpload.DataBind();
                                //lblMsg.Visible = false;

                                //บันทึกลง Mysql
                                foreach (GridViewRow g1 in grvBatchUpload.Rows)
                                {
                                    objConn = new MySqlConnection(strConnString);

                                    strSQL = "insert into WBS (ASSET,SNO,CODEID,BP,HEADELECTRICITY,DEF,WBS_NO,STATUS1,STATUS2,TECHNICIAN,SECTION,RESP,MEMBER,YEAR,DESCRIPTION) values('" + g1.Cells[0].Text + "','" + g1.Cells[1].Text + "','" + g1.Cells[2].Text + "','" + g1.Cells[3].Text + "','" + g1.Cells[4].Text + "','" + g1.Cells[5].Text + "','" + g1.Cells[6].Text + "','" + g1.Cells[7].Text + "','" + g1.Cells[8].Text + "','" + g1.Cells[9].Text + "','" + g1.Cells[10].Text + "','" + g1.Cells[11].Text + "','" + g1.Cells[12].Text + "','" + g1.Cells[13].Text + "','" + g1.Cells[14].Text + "') ";

                                    objCmd = new MySqlCommand(strSQL, objConn);
                                    objConn.Open();
                                    objCmd.ExecuteNonQuery();
                                    objConn.Close();
                                }
                                lblMsg.Visible = true;
                                lblMsg.Style.Add("color", "blue");
                                lblMsg.Text = "Import ข้อมูลเสร็จเรียบร้อย";
                                //end mysql
                            }
                            else
                            {

                                lblMsg.Visible = true;
                                lblMsg.Style.Add("color", "red");
                                lblMsg.Text = "ไม่พบข้อมูลในไฟล์นี้ !!!";
                            }
                            FilePath = ResolveUrl("~/Uploads/");
                            string fileName = Server.MapPath(FilePath) + filename;
                            FileInfo f = new FileInfo(fileName);
                            if (f.Exists)
                            {
                                f.IsReadOnly = false;
                                f.Delete();
                            }
                        }
                        else
                        {
                            lblMsg.Visible = true;
                            lblMsg.Style.Add("color", "red");
                            lblMsg.Text = "ขนาดไฟล์ Excel ไม่เกิน 1 MB !!!";
                        }
                    }
                }
                catch (Exception ex)
                {
                    lblMsg.Visible = true;
                    lblMsg.Style.Add("color", "red");
                    lblMsg.Text = "พบข้อผิดพลาดขณะทำการ Import ข้อมูล : " + ex.Message;
                }
            }
            else
            {
                lblMsg.Visible = true;
                lblMsg.Style.Add("color", "red");
                lblMsg.Text = "กรุณาเลือกไฟล์ที่ต้องการ Import !!!";
            }
        }
        protected void btnUpload_Click(object sender, EventArgs e)
        {
            //แสดงข้อมูลจาก Excel เข้า Gridview
            BindGridView();
        }
    }
}