I downloaded the instant package and unzipped it in koolreport folder. I tried the very first example of the instant package and got this error.

<?php
    require_once APPPATH."/libraries/koolreport/autoload.php";
    use \koolreport\instant\Widget;
    use \koolreport\widgets\google\BarChart;
?>
<html>
    <head>
        <title>Instant BarChart</title>
    </head>
    <body>
    <?php
    Widget::create(BarChart::class,array(
        "data"=>array(
            array("name"=>"Peter","age"=>35),
            array("name"=>"Karl","age"=>32),
        )
    ));
    ?>
    </body>
</html>