I don't get it, my code works, but I get an error message

<?php
//edit this array
        $contacts = array(array('name' => 'Alena Holligan', 'email' => 'alena.holligan@teamtreehouse.com'), 
                          array('name' => 'Dave McFarland', 'email' => 'dave.mcfarland@teamtreehouse.com'),
                          array('name' => 'Treasure Porth', 'email' => 'treasure.porth@teamtreehouse.com'),
                          array('name' => 'Andrew Chalkley', 'email' => 'andrew.chalkley@teamtreehouse.com')
                        );

echo "<ul>\n";
//$contacts[0] will return 'Alena Holligan' in our simple array of names.
echo "<li>" . $contacts[0]['name'] . ":" . $contacts[0]['email'] . "</li>\n";
echo "<li>" . $contacts[1]['name'] . ":" . $contacts[1]['email'] . "</li>\n";
echo "<li>" . $contacts[2]['name'] . ":" . $contacts[2]['email'] . "</li>\n";
echo "<li>" . $contacts[3]['name'] . ":" . $contacts[3]['email'] . "</li>\n";
echo "</ul>\n";