Excel 응용 프로그램의 Exception from HRESULT: 0x800A03EC 정보

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Xml.Linq;
using Microsoft.Office.Tools.Excel;
using Microsoft.VisualStudio.Tools.Applications.Runtime;
using Excel = Microsoft.Office.Interop.Excel;
using Office = Microsoft.Office.Core;

namespace ExcelWorkbook6
{
    public partial class ThisWorkbook
    {
        private void ThisWorkbook_Startup(object sender, System.EventArgs e)
        {
            try
            {
                Excel.Range objRage = Application.ActiveCell;
                string formula1 = @"=A5/0";
                objRage.Validation.Delete();
                objRage.Validation.Add(Excel.XlDVType.xlValidateList, Excel.XlDVAlertStyle.xlValidAlertStop, Type.Missing, formula1, Type.Missing);
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        private void ThisWorkbook_Shutdown(object sender, System.EventArgs e)
        {
        }

        #region VSTO Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisWorkbook_Startup);
            this.Shutdown += new System.EventHandler(ThisWorkbook_Shutdown);
        }

        #endregion

    }
}