Zend Translate doesn't find language

I've got a Zend Translate Issue. I have configure the zend translate in the bootstrap like below

public function _initTranslate() {
    $locale = new Zend_Locale();
    Zend_Registry::set('Zend_Locale', $locale);

    $translate = new Zend_Translate(array(
                'adapter' => 'ini'
                    )
    );

    $translate->addTranslation(
            array(
                'content' => APPLICATION_PATH . '/configs/languages/pt.ini',
                'locale' => 'pt'
            )
    );
    $translate->addTranslation(
            array(
                'content' => APPLICATION_PATH . '/configs/languages/en.ini',
                'locale' => 'en'
            )
    );

    $translate->setLocale($locale);
    Zend_Registry::set('Zend_Translate', $translate);
}

I've added the languages and in my views I used translate helper but it shows me the following erros

Notice: The language 'en' has to be added before it can be used. 
in C:\xampp\ZendFramework-1.11.10\library\Zend\Translate\Adapter.php 
on line 443
Notice: No translation for the language 'en' available. 
in C:\xampp\ZendFramework-1.11.10\library\Zend\Translate\Adapter.php 
on line 456

I've followed zendframework reference guide. What I am doing wrong?

I solved ths issue with the code below:

public function _initTranslate() {
    $this->bootstrap('locale');
    if($this->hasResource('locale')){
        $locale = $this->getResource('locale');
    }

    $translate = new Zend_Translate(array(
                'adapter' => 'ini',
                'disableNotices' => true,
                )
    );

    $translate->getAdapter()->addTranslation(
            array(
                'content' => APPLICATION_PATH . '/configs/languages/pt.ini',
                'locale' => 'pt'
            )
    );
    $translate->getAdapter()->addTranslation(
            array(
                'content' => APPLICATION_PATH . '/configs/languages/en.ini',
                'locale' => 'en'
            )
    );
    if($translate->getAdapter()->isAvailable($locale->getLanguage())){
        $translate->getAdapter()->setLocale($locale->getLanguage());
    }else{
        $translate->getAdapter()->setLocale('en');
    }
    Zend_Registry::set('Zend_Locale', $locale);
    Zend_Registry::set('Zend_Translate', $translate);
}

And I coded a plugin to change language at runtime by just passing a GET variable Ex.: &lang=en

class Sistema_Plugin_Translate extends Zend_Controller_Plugin_Abstract {

    public function preDispatch(Zend_Controller_Request_Abstract $request) {

        $translate = Zend_Registry::get('Zend_Translate');
        $locale = Zend_Registry::get('Zend_Locale');
        $session = new Zend_Session_Namespace('language');

        //verifica se existe GET e valida
        if ($request->isGet()) {
            $filter = new Zend_Filter_Alpha();
            $param = $filter->filter($request->getParam('lang'));
            if (!empty($param) && $locale->isLocale($param) && $translate->getAdapter()->isAvailable($param)) {
                $translate->getAdapter()->setLocale($param);
                $session->language = $param;
            }
        }

        //verifica se o idioma do browser está disponivel se não coloca um idioma padrão
        if (!$translate->getAdapter()->isAvailable($locale->getLanguage())) {
            //linguagem não disponivel,seta idioma en
            $translate->getAdapter()->setLocale('en');
        }

        //verifica se há sessão com idioma definido
        if (isset($session->language)) {
            if ($translate->getAdapter()->isAvailable($session->language)) {
                $translate->getAdapter()->setLocale($session->language);

            }
        }


    }

}