At page 472 (Chapter 12) in the code for class User() is think there's a flaw that brings up the Exception error in the __set function. This is caused by the fact that $_changedProperties is not initialised at the beginning of the whole class declaration. Where the class statement now reads:
Code:
class User {
private $_properties;
private $_hDB;
public function __construct($userID){
ETC.
it should read
Code:
class User {
private $_properties;
private $_hDB;
private $_changedProperties;
public function __construct($userID){
ETC.
At least this is the only way I could avoid the Exception error (apart from commenting out the $_changedProperties in the constructor function).
John