Coursepress unit preview internal server error

Hey guys,

Hope you're fine.

Since the last beta update, visitors are not able to access to free units from the course structure on a course page. They get an internal server error. However, if a user is logged in, he can access the free unit.

You can try it on a course page : http://elearning.thedawahtv.fr/courses/

Thx for your time.