cost_utils.php, Language, Previous and next Events

Hi,
like i wrote already in the forum https://theeventscalendar.com/support/forums/topic/cost_utils-php-german-translation/
I have 3 problems since 4.0 (that I know of right now)

1. all free events where marked with “Freier Eintritt” I get error warnings now an all free events from the past.
2. The german translation at the end is missing. There is now “previous Veranstaltungen (Events)” or “Next Veranstaltungen”

3. These Links “previous Veranstaltungen (Events)” or “Next Veranstaltungen” do not work anymore. It jumps from the december to August and the month in between are missing. Can you help?
http://die-kulturquelle.de

https://wordpress.org/plugins/the-events-calendar/