c# export to excell not working on some computers

Question

I have below code in order to export excel

 System.IO.MemoryStream stream = new System.IO.MemoryStream();

using (SpreadsheetDocument document = SpreadsheetDocument.Create(stream, SpreadsheetDocumentType.Workbook, true))
{
   WriteExcelFile(ds, document);
}

   stream.Flush();
   stream.Position = 0;

   Response.ClearContent();
   Response.Clear();
   Response.Buffer = true;
   Response.Charset = "";

   Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache);
   Response.AddHeader("content-disposition", "attachment; filename=" + filename);
   Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";


   byte[] data1 = new byte[stream.Length];
   stream.Read(data1, 0, data1.Length);
   stream.Close();
   Response.BinaryWrite(data1);
   Response.Flush();
   Response.End();

Almost all computers does not have any problem while exporting data from dataset to excel with above code.However in some computers there is an error as below.

Error:

NullReferenceException: Object reference not set to an instance of an object

Stack

[NullReferenceException: Object reference not set to an instance of an object.]

Project.Excel_Export.CreateDataSourceNew() in d:\Projects\Rapor\Excel_Export.aspx.cs:146

Project.Excel_Export.bagla() in d:\Projects\Rapor\Excel_Export.aspx.cs:129

Project.Excel_Export.Page_Load(Object sender, EventArgs e) in d:\Projects\Rapor\Excel_Export.aspx.cs:91




 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
 System.Web.UI.Control.OnLoad(EventArgs e) +99
 System.Web.UI.Control.LoadRecursive() +50
 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627

If i run project on local there is no any error . Only some of computers have this error while exporting to excel.

What is problem with some computers that having error while exporting excel ?

Problem might be about server or excel release in computer ?

Where i miss and how can i solve this problem.

Any help will be appreciated.

Thanks.