G'day tbodine88,

Welcome to the monastery.

From Spreadsheet::XLSX's source code on CPAN:

sub new {

    my ($class, $filename, $converter) = @_;
    
    my $self = {};
    
    $self -> {zip} = Archive::Zip -> new ();

    if (ref $filename) {
    
        $self -> {zip} -> readFromFileHandle ($filename) == Archive::Z
+ip::AZ_OK or die ("Cannot open data as Zip archive");
    
    } 
    else {
    
        $self -> {zip} -> read ($filename) == Archive::Zip::AZ_OK or d
+ie ("Cannot open $filename as Zip archive");
    
    };
        ...
}
[download]

Line 28 is the one with the "Cannot open data as Zip archive" message you're getting. When you "tried uploading and copying to a file", did you get the line 33 error message?

If this is working when you download via FTP, but not working when uploading via CGI, this suggests you may have a problem with your upload code (which you haven't shown).

Not having seen your CGI code, these are just suggestions which may prove fruitful. Take a look at CGI: PROCESSING A FILE UPLOAD FIELD. There's a lot of useful information there including example code. Also, look at CGI: Avoiding Denial of Service Attacks. See what it says about uploads here and look at the information about the $CGI::POST_MAX and $CGI::DISABLE_UPLOADS variables.

You may also want to consider using Spreadsheet::ParseXLSX instead of Spreadsheet::XLSX. The former is being actively maintained; the latter hasn't been touched in four years and has dozens of outstanding bugs.