Exception from HRESULT: 0x800A03EC. with excel program in C#

Exception Details: System.Runtime.InteropServices.COMException: Exception from HRESULT: 0x800A03EC.

Source Error:


Line 32:                   xlApp.Visible = true;
Line 33:                   string strFileName = sFileName;
Line 34:                   Excel.Workbook xlWB =  xlApp.Workbooks.Open("ExcelData.xls",
Line 35:                         null,
Line 36:                         null,
 

Source File: c:\inetpub\wwwroot\webapplication1\webform2.aspx.cs    Line: 34

Code:

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Diagnostics;
using System.Reflection;
using Excel= Microsoft.Office.Interop.Excel;
using System.Data.OleDb;
using System.IO;
using System.Text;
using System.Runtime.InteropServices; // For COMException

namespace WebApplication1
{
      /// <summary>
      /// Summary description for WebForm2.
      /// </summary>
      public class WebForm2 : System.Web.UI.Page
      {
            protected Excel.Application xlApp;
            protected Excel.Workbook xlWB1;
                  
            private void searchExcelSpreadSheet(string sFileName)
            {
                  Excel.Application xlApp = new Excel.Application();
                  xlApp.Visible = true;
                  string strFileName = sFileName;
                  Excel.Workbook xlWB =  xlApp.Workbooks.Open("ExcelData.xls",
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null,
                        null);
                  Excel.Worksheet xls = (Excel.Worksheet)xlWB.Sheets[1];

                  int intRows, intCols, r, c;

                  intRows = xls.UsedRange.Rows.Count;
                  intCols = xls.UsedRange.Columns.Count;

                  for(r = 1; r < intRows; r++)
                  {
                        for(c=1; c < intCols; c++)
                        {
                              string text = (string)((Excel.Range)xls.Cells[r,c]).Text;
                              Response.Write (text+"<br>");
                        }
                  }
               
                  xlWB.Close(false, null, null);
                  xlApp.Quit();
                  xls = null;
                  xlWB = null;
                  xlApp = null;

            }

            
            private void Page_Load(object sender, System.EventArgs e)
            {
                  // Put user code to initialize the page here
                  searchExcelSpreadSheet ("\\Excel\\ExcelData.xls");

            }

            #region Web Form Designer generated code
            override protected void OnInit(EventArgs e)
            {
                  //
                  // CODEGEN: This call is required by the ASP.NET Web Form Designer.
                  //
                  InitializeComponent();
                  base.OnInit(e);
            }
            
            /// <summary>
            /// Required method for Designer support - do not modify
            /// the contents of this method with the code editor.
            /// </summary>
            private void InitializeComponent()
            {    
                  this.Load += new System.EventHandler(this.Page_Load);
            }
            #endregion
      }
}