I assume you already set spanish as the main language in your admin panel. If this problem is due to the language pack, one thing that you could try is rename the file /home/orfvrays/public_html/zen/admin/includes/languages/spanish/credit_cards.php and replace it by the original one in english in include/language/english and see if it works.

If it works compare the two file and see what the difference is between the two version and make the necessary change.