It's not me mixing up "/" and "\", judge for yourself:

use strict;
use warnings;
use Chart::Gnuplot;

    my $chart = Chart::Gnuplot->new(
        output => "c:/tmp/test.png",
        title  => "Simple testing",
        xlabel => "My x-axis label",
        ylabel => "My y-axis label",
        gnuplot => "C:/gnuplot/binaries/wgnuplot.exe",
    );

    my $dataSet = Chart::Gnuplot::DataSet->new(
        func => "sin(x)"
    );

    $chart->plot2d($dataSet);
    
    print "Done...\n";
[download]

Resulting in the familiar error message;-)

try this:

use strict;
use warnings;
use Chart::Gnuplot;

    my $chart = Chart::Gnuplot->new(
        output => 'c:\tmp\test.png',
        title  => 'Simple testing',
        xlabel => 'My x-axis label',
        ylabel => 'My y-axis label',
        gnuplot => 'C:\gnuplot\binaries\wgnuplot.exe',
    );

    my $dataSet = Chart::Gnuplot::DataSet->new(
        func => 'sin(x)'
    );

    $chart->plot2d($dataSet);
    
    print "Done...\n";
[download]

(notice the single quotes and the backslashes...)

What is the result?

[]s, HTH, Massa (κς,πμ,πλ)

Result: util.c: Invalid argument

If I comment the gnuplot line and use the bat file approach the message is: C:\workspace\Testbed>"C:\gnuplot\binaries\wgnuplot.exe" \tmp\yZ35R2dy8v/plot

I think I am developing an understanding why it's not working, see my response to BrowserUK.

Cheers,
dHarry