Corion I read that and done program with that. But its not "overwriting" my xlsx file.

# Open an existing file with SaveParser
my $parser   = Spreadsheet::ParseExcel::SaveParser->new();
my $template = $parser->Parse('B_MUM_dashboard_month_latency_corrected
+_FDB.XLS');

# Get the first worksheet.
my $sheet = $template->worksheet(0);
my $row  = $max_rows;
my $col  = 1;

while (my @row = $sth->fetchrow_array())
{
        foreach my $value (@row)
        {
        $sheet->AddCell( $row, $col, $value );
        ++$col;
    }
}
$template->SaveAs('B_MUM_dashboard_month_latency_corrected_FDB.XLS');
[download]

Its working very well for .xls files. But I want to "overwrite" .XLSX files