Hi Suzanne. Thanks for the note, and sorry to hear that you’re having problems. The majority of translations are controlled by that events-calendar.po file; the only purpose of the events-calendar-pro.po file is to translate the views/words that are included in the PRO add-on but not in free.
Remember that you also need to include a .mo file (which should be auto generated upon saving your translation in POEdit) for each, and that you need to change your language in the wp-config file as well. It possible that you’d missed one of those steps?