Firstly I would check to see your locale settings for the store. You can check this under System -> Configuration -> General -> General, then the Locale Options -> Locale field.
Assuming you are using "United States" as your locale for your store I would clear the translations and block caches as any changes you make to those translate.csv files won't appear until the cache is cleared.
If at this point they are not appearing I would check that your theme is not using a different theme for translations under System -> Configuration -> General-> Design, then Themes -> Translations field.
Another possibility could be that their maybe inline (database) translations. This would have higher priority over module (app/locale) or theme translations (package/theme/locale/) files as Magento gives inline translations the highest priority.
You can turn on inline translations by going to System -> Configuration -> Advanced -> Developer, then setting Translate Inline -> "Enable for frontend" to "Yes" and clearing the Magento cache and then viewing your Magento store (shouldn't be done on live unless you add your IP to Developer Restrictions on the same configuration page) you should see red dotted line around the text you can edit and when you hover you should see a book icon which you can click to edit and then save the text.
You can read more about translations on how they work here - http://blog.belvg.com/magento-certified-developer-exam-internationalization.html