Doing my digging and it appears this is chapter 4. Code from the sample:
<?php
Require_once("e10dog.php");
$lab = new Dog;
// ------------------------------Set Properties--------------------------
$dog_error_message = $lab->set_dog_name('Fred');
print $dog_error_message == TRUE ? 'Name update successful<br/>' : 'Name update not successful<br/>';
Note the lack of 'bool' before $dog_error_message. I'm not trying to be a jackass here, but when you're learning a language you have to read the tutorials completely, follow them accurately, and listen to the people who know what they're talking about when they try to help with any confusion.