Error code

Notice (8): Undefined index: categories [APP/Controller/AppController.php, line 158]
Code Context
            //Loop throug categories to search if have cards
            $return['data']['cards'] = FALSE;
            foreach ($return['data']['categories'] as $cat) {
$appID = '211070'
$currency = 'en'
$cacheName = 'gamesInfo'
$return = array(
	'success' => false,
	'data' => array(
		'cards' => false
	)
)
$url = 'http://store.steampowered.com/api/appdetails?appids=211070&cc=en'
$json = array(
	(int) 211070 => array(
		'success' => false
	)
)
AppController::getAppInfo() - APP/Controller/AppController.php, line 158
AjaxController::couponUserModal() - APP/Controller/AjaxController.php, line 41
ReflectionMethod::invokeArgs() - [internal], line ??
Controller::invokeAction() - CORE/Cake/Controller/Controller.php, line 490
Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 193
Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 167
[main] - APP/webroot/index.php, line 116
Warning (2): Invalid argument supplied for foreach() [APP/Controller/AppController.php, line 158]
Code Context
            //Loop throug categories to search if have cards
            $return['data']['cards'] = FALSE;
            foreach ($return['data']['categories'] as $cat) {
$appID = '211070'
$currency = 'en'
$cacheName = 'gamesInfo'
$return = array(
	'success' => false,
	'data' => array(
		'cards' => false
	)
)
$url = 'http://store.steampowered.com/api/appdetails?appids=211070&cc=en'
$json = array(
	(int) 211070 => array(
		'success' => false
	)
)
AppController::getAppInfo() - APP/Controller/AppController.php, line 158
AjaxController::couponUserModal() - APP/Controller/AjaxController.php, line 41
ReflectionMethod::invokeArgs() - [internal], line ??
Controller::invokeAction() - CORE/Cake/Controller/Controller.php, line 490
Dispatcher::_invoke() - CORE/Cake/Routing/Dispatcher.php, line 193
Dispatcher::dispatch() - CORE/Cake/Routing/Dispatcher.php, line 167
[main] - APP/webroot/index.php, line 116