Sythe on "[Plugin: Booking System (Booking Calendar)] Dutch language bug"

When I try to use the dutch version of the plugin, it won't load and I get an error. I want to know if it works before I buy the PRO version of this plugin.

I'm using the dutch language this way:
[dopbs lang=nl]

I get this error:
https://www.dropbox.com/s/yaezd26r28hac7l/Screenshot%202014-02-21%2011.12.22.png

And this is what I see on the website:
https://www.dropbox.com/s/zu4q824a0qn2rw9/Screenshot%202014-02-21%2011.12.45.png

Can someone please help me?

https://wordpress.org/plugins/booking-system/