Are you sure that the error occurs when adding the workbook?
I guess it is happening when adding the sheet with
xlWorkSheet = xlWorkBook.Sheets.Add("Sheet1")
The first parameter specifies the sheet before which the new sheet is added (see
Worksheets.Add method (Microsoft.Office.Interop.Excel)[
^]). But if there is no sheet named "Sheet1", the call will fail with 0x800A03EC (NAME_NOT_FOUND).
Use
xlWorkSheet = xlWorkBook.Sheets.Add()
instead.