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>