input type=“file" を入れるとフォーム送信ができない

エラー: The request sent to the address '/members/pr_contents/add' was invalid.

$this->BcForm->create('PrContent', array('type'=>'file', 'action' => 'add', 'url' => array(), 'class' => 'form-horizontal’))

$this->BcForm->file('PrContent.img1’)

$this->BcForm->input('PrContent.img1', array('type'=>'file’))

$this->BcUpload->file('PrContent.img1’)

Stack Trace
    [internal function] → BcAppController->_blackHoleCallback(string)
    CORE/Cake/Controller/Component/SecurityComponent.php line 622 → call_user_func_array(array, array)
    CORE/Cake/Controller/Component/SecurityComponent.php line 337 → SecurityComponent->_callback(PrContentsController, string, array)
    CORE/Cake/Controller/Component/SecurityComponent.php line 239 → SecurityComponent->blackHole(PrContentsController, string)
    [internal function] → SecurityComponent->startup(PrContentsController)
    CORE/Cake/Utility/ObjectCollection.php line 128 → call_user_func_array(array, array)
    [internal function] → ObjectCollection->trigger(CakeEvent)
    CORE/Baser/Event/CakeEventManager.php line 245 → call_user_func(array, CakeEvent)
    CORE/Cake/Controller/Controller.php line 677 → CakeEventManager->dispatch(CakeEvent)
    CORE/Cake/Routing/Dispatcher.php line 189 → Controller->startupProcess()
    CORE/Cake/Routing/Dispatcher.php line 167 → Dispatcher->_invoke(PrContentsController, CakeRequest)
    APP/webroot/index.php line 151 → Dispatcher->dispatch(CakeRequest, CakeResponse)