In the storage_location\joomla_article\joomla_article.php file, there are 2 places where problems occur from checking for an unset array value.
They are line 104 and 112 where it shows:
if ( $config['translate_id'] ) {}
instead of
if ( array_key_exists($config, 'translate_id') && $config['translate_id'] ) {}
If the array key doesn't exist in the first example, it will throw a PHP notice because $config['translate_id'] is not set, not even to NULL.