Import from excel to grid view not working on some machines

Protected Sub btnUpload_Click(sender As Object, e As EventArgs) Handles btnUpload.Click
       Try
           If FileUpload2.HasFile Then
               Dim FileName As String = Path.GetFileName(FileUpload2.PostedFile.FileName)
               Dim Extension As String = Path.GetExtension(FileUpload2.PostedFile.FileName)
               Dim FolderPath As String = ConfigurationManager.AppSettings("Folderpath")

               Dim FilePath As String = Server.MapPath(FolderPath + FileName)

               FileUpload2.SaveAs(FilePath)

               Import_To_Grid(FilePath, Extension, rbHDR.SelectedItem.Text)
           End If
       Catch ex As Exception
           fnMessage(Me, ex.Message)
       End Try

   End Sub