If your admin interface is set in spanish, the online editor is loaded in spanish too.
Does your admin siteaccess have the following settings in site.ini.append?
[RegionalSettings]
Locale=esl-ES
Note also that the more up to date translation is available here: http://ez.no/community/contribs/internationalization/online_editor_4_1_spanish_translation
The ez publish instalation is a complete new on a development server. EzP was installed with spanish as only language and the siteaccess file have following lines in site.ini.append.php in the corporate_site_admin folder:
Try to clear all your cache and just after clearing enter first in the admin siteaccess. I have already seen some caching trouble with ezoe if you enter first in the public siteaccess.
To clear all the cache, do it from the admin interface or via :