Тот код замените на этот:
if (isset($this->request->get['currency']) && (array_key_exists($this->request->get['currency'], $this->currencies))) {
$this->set($this->request->get['currency']);
} elseif ((isset($this->session->data['currency'])) && (array_key_exists($this->session->data['currency'], $this->currencies))) {
$this->set($this->session->data['currency']);
} elseif ((isset($this->request->cookie['currency'])) && (array_key_exists($this->request->cookie['currency'], $this->currencies))) {
$this->set($this->request->cookie['currency']);
} else {
if ($this->has('RUB')) {
$this->set('RUB');
} else {
$this->set($this->config->get('config_currency'));
}
}
