Mandatory information about my setup:

Have I searched the tickets before posting? Yes
Have I searched the forum before posting? Yes
Have I read the documentation before posting (which pages?)? No
Joomla! version: 2.5.28
PHP version: 5.5.0
MySQL version: 5.5.40
Matukio version: 5.1.3
Direct link to the page that shows the issue:
http://www.breloer.de/trainingsuebersicht.html

Description of my issue:
When i click on event details, i get the 404 Error Page, same Error while i try to finish the booking.