Win32::GetLastError will only return a meaningfull value if called immediately after the system call. It most likely doesn't return Excel-specific information, so likely you're out of luck with your strategy of trying to find out something more specific about the error condition.

There seems to be no way to convince Excel to save the file unconditionally with the ->SaveAs method, overwriting what is potentially there, so I think you'll have to use

$excel->{DisplayAlerts} = 0;
$excel->Workbooks(1)->SaveAs( $sp_full );
[download]

The documentation doesn't say much on using the return value of ->SaveAs, so you might have to guess whether it worked or not.

There seems to be no way to convince Excel to save the file unconditionally with the ->SaveAs method, overwriting what is potentially there

You could copy the spreadsheet to the new name before opening and modifying it.

merrymonk ,

From MSDN:

ERROR_MR_MID_NOT_FOUND 317 The system cannot find message text for message number 0x%1 in the message file for %2.

The $en_f = Win32::FormatMessage($en_num); can't provide a string because the text that would be used for that string doesn't exist.

ikegami's suggestion may point to this:

From CPAN:

Win32::CopyFile(FROM, TO, OVERWRITE)

CORE The Win32::CopyFile() function copies an existing file to a new file. All file information like creation time and file attributes will be copied to the new file. However it will not copy the security information. If the destination file already exists it will only be overwritten when the OVERWRITE parameter is true. But even this will not overwrite a read-only file; you have to unlink() it first yourself.

$excel->{DisplayAlerts}=1; I get a message indicating that the file is there and asking if I want to overwrite it.

Looking at the above, I believe the error has to do with an attempt to overwrite an existing file(The very file you have open).

Using the Win32::CopyFile(FROM, TO, OVERWRITE) to allow the overwrite may solve the problem.

Thank you for the comments and help which stopped m looking in crypts that would have nothing in them!
I have done more work and to help I used the sub below.
I believe that I have found that the problem was caused by having a directory
that contained ‘[]’ characters since when I removed these all was well.
It would interesting to know if these characters are not ‘preferred’ in some sense.
To confuse matters, I have a suspicion that this will not be found on all PCs under windows but I cannot be sure


sub copy_edit_savesp_test($$$) {

my ($file_name, $dir_in, $dir_out) = @_;

my ($file_name_in_full, $file_name_out_full, $excel, $excel_res, $work
+book, $copy_res);
my ($add_data_sp, $row, $workbook_res, $ew_message, $wksht, $wksht_str
+, $worksheet);

$file_name_in_full = $dir_in . '\\' . $file_name;
$file_name_out_full = $dir_out . '\\' . $file_name;

$copy_res = copy($file_name_in_full, $file_name_out_full);

print "\ndir file <$file_name>\nin <$dir_in>\n$dir_out\n";


print "\n[copy_edit_savesp_test] copy res <$copy_res> for <$file_name_
+out_full>\n";


$excel_res = 1;

$excel = Win32::OLE->new('Excel.Application', 'Quit') or ($excel_res =
+ 0, $ew_message = "Could not create excel object");

print "[copy_edit_savesp_test] open res <$excel_res> excel <$excel> wo
+rkbook <$workbook>\n";

if($excel_res == 1) {

    $workbook_res = 1;
    $ew_message = "work book ok";

    $workbook = $excel->Workbooks->Open($file_name_out_full)  or ($wor
+kbook_res = 0, $ew_message = "Could not open excel workbook");

    print "[copy_edit_savesp_test] after workbook result <$workbook_re
+s> message <$ew_message>\n";

    $add_data_sp = 'yes';

    if($add_data_sp eq 'yes') {

        $wksht +=1;
        $wksht_str = "sheet" . $wksht;

        $worksheet = $excel->ActiveWorkbook->Worksheets($wksht_str);

        $row = 2;
        $worksheet->Cells($row,9)->{Value} = "row $row 9";

        $row = 3;
        $worksheet->Cells($row,6)->{Value} = "row $row 6";

        $worksheet->Cells($row,8)->{Value} = "row $row 8";

    } else {

        print "\n[copy_edit_savesp_test]no data added to spredsheet\n"
+;
    }
}


$excel->{DisplayAlerts}=0;   

$ew_message = "just before saving spreadsheet";
print "before message <$ew_message>\n";

$excel_res = 1;
$excel->Workbooks(1)->SaveAs($file_name_out_full)  or ($excel_res = 0,
+ $ew_message = "Could not save spreadsheet>");

print "[copy_edit_savesp_test] after saving spredsheet result <$excel_
+res> message <$ew_message>\n\n";

$excel->{DisplayAlerts}=1;   



}
[download]

use Win32;
use Win32::OLE;
use Win32::OLE::Const 'Microsoft Excel';
[download]

     $excel = Win32::OLE->new('Excel.Application', 'Quit') or ($excel_
+res = 0, $ew_message = "Could not create excel object");
$workbook = $excel->Workbooks->Open($new_finnpower_full)  or ($workboo
+k_res = 0, $ew_message = "Could not open excel workbook");
[download]

GetLastError is only meaningful after a system call returns an error. It's wrong to use it there.