Invalid Pointer and Access Violation with Native Excel 3 for Delphi - delphi

Question

I'm using Delphi 10.2 and the Native Excel 3 library to create spreadsheets.
I have the following code:
var
fWorkbook: IXLSWorkbook;
fSheet1: IXLSWorksheet;
begin
fWorkbook:=TXLSWorkbook.Create;
fSheet1:=fWorkBook.Sheets.Add;
fSheet1.Range['A1','A1'].ColumnWidth:=20;
fSheet1.Range['B1','B1'].ColumnWidth:=20;
fSheet1.Range['C1','C1'].ColumnWidth:=32;
fSheet1.Range['D1','D1'].ColumnWidth:=32;
fSheet1.Range['E1','E1'].ColumnWidth:=14;
fSheet1.Range['F1','F1'].ColumnWidth:=14;
fSheet1.Range['G1','G1'].ColumnWidth:=14;
fSheet1.Range['H1','H1'].ColumnWidth:=14;
fSheet1.Range['I1','I1'].ColumnWidth:=14;
fSheet1.Cells[1,1].Value:='Entry Type';
fSheet1.Cells[1,2].Value:='Intacct Acct #';
fSheet1.Cells[1,3].Value:='Intacct Acct # Description';
fSheet1.Cells[1,4].Value:='Store Name';
fSheet1.Cells[1,5].Value:='Department #';
fSheet1.Cells[1,6].Value:='Location ID';
fSheet1.Cells[1,7].Value:='Project ID';
fSheet1.Cells[1,8].Value:='Grant ID';
fSheet1.Cells[1,9].Value:='Net Amount';
intRow:=fWorkBook.SaveAs(Outfile);
'there is additional code after this.
end;
This code works every time on my development system. I've also used nExcel in other projects without a problem.
However, at the client's system, the fWorkbook.SaveAs generates an "Invalid Pointer" error or Access Violation. Since I cannot duplicate it, debugging is tough.
I have tried moving the SaveAs to various places (after the initial create, after the setting of column widths and where it is now).
Anyone seen this and/or have an explanation?
Thanks!
Malcolm

Answer 1

This problem was resolved by saving the workbook as an xlsx.