[Plugin: All-in-One Event Calendar] Translation problem

I recently installed the calendar plugin on my website, and really like the way it looks and feels. However, I can’t seem to get the translation right.
I have the right (dutch) translation file in use, but it doesn’t seem to cover all the english words in the calendar.

For example, in the weekly view of the calendar, the “previous” and “next” buttons to browse through the weeks are called “week of januari 15” and “week of januari 29”. I would like to translate these to “week van 15 januari” en “week van 29 januari”.

Is there a file in the plugin files where I can change this? Or is this problem caused by the overall wordpress translation?