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?