notice error on arrayObject - php

Question

Hello i'm having trouble with this class when it comes to multidimensional arrays and setting them and i cannot understand why is behaving like this...
Anyone who can help me fix it?
Few Usage Examples:
echo $config->session->gcDivisor;
echo $config['session']['gcDivisor'];
$config['logged'] = '1';
$config->logged = '1';
$config['user']['logged'] = '1';
$config->user->logged = '1';
Errors for each of the lines
Notice: Trying to get property of non-object in /home/biroexpert/subdomains/prod/index.php on line 33
200
Notice: Undefined index: user in /home/biroexpert/subdomains/prod/Library/Twelve/Config/Config.php on line 67
Notice: Indirect modification of overloaded element of Twelve\Config\Config has no effect in /home/biroexpert/subdomains/prod/index.php on line 37
Notice: Undefined index: user in /home//subdomains/prod/Library/Twelve/Config/Config.php on line 87
Notice: Indirect modification of overloaded property Twelve\Config\Config::$user has no effect in /home//subdomains/prod/index.php on line 38
Strict Standards: Creating default object from empty value in /home//subdomains/prod/index.php on line 38
Code
<?php
namespace Twelve\Config;
use \ArrayObject;
use \Twelve\SingletonPattern\LazySingleton;
use \Twelve\SingletonPattern\Interfaces\ILazySingleton;
/**
* Singleton With Configuration Info
*/
class Config extends ArrayObject implements ILazySingleton
{
/**
* Stores FileName
* #var Config
*/
protected static $_configFile = '';
/**
* Config Settings Array
* #var Config
*/
protected $_settings = array();
public static function getInstance(){
return LazySingleton::getInstance(__CLASS__);
}
/**
* Set the Config File Path
*/
public static function setFile($filePath)
{
static::$_configFile = $filePath;
}
public function __construct()
{
LazySingleton::validate(__CLASS__);
$values = include(static::$_configFile);
if(is_array($values))
{
// Allow accessing properties as either array keys or object properties:
$this->_settings = new ArrayObject($values, ArrayObject::ARRAY_AS_PROPS);
}
}
// some debug method
public function dumpArray()
{
echo "<pre>";
print_r($this->_settings);
}
public function getIterator()
{
return $this->_settings->getIterator();
}
public function offsetExists($index)
{
return $this->_settings->offsetExists($index);
}
public function offsetGet($index)
{
return $this->_settings->offsetGet($index);
}
public function offsetSet($key, $value)
{
return $this->_settings->offsetSet($key, $value);
}
public function offsetUnset($index)
{
return $this->_settings->offsetUnset($index);
}
public function count()
{
return $this->_settings->count();
}
/**
* Prevent Cloning
*/
public function __clone()
{
trigger_error('Clone is not allowed.', E_USER_ERROR);
// No Cloning Allowed
}
}