ลองช่วยดูหน่อยค่ะ ว่ามัน error เพราะอะไร มีใครรู้ช่วยทีนะคะ

<?php
$php = new Runkit_Sandbox();
$php['parent_access'] = true;
$php['parent_read'] = true;

$test = "Global";

$php->eval('$PARENT = new Runkit_Sandbox_Parent;');

$php['parent_scope'] = 0;
one();

$php['parent_scope'] = 1;
one();

$php['parent_scope'] = 2;
one();

$php['parent_scope'] = 3;
one();

$php['parent_scope'] = 4;
one();

$php['parent_scope'] = 5;
one();

function one() {
    $test = "one()";
    two();
}

function two() {
    $test = "two()";
    three();
}

function three() {
    $test = "three()";
    $GLOBALS['php']->eval('var_dump($PARENT->test);');
}
?>