TOPIC: Error message on Register for an Event

HI
Since the last update do i get an error when i tray to register for an event:

Warning: Illegal string offset 'Setting' in /home/ralphcas/www/activepeople/administrator/components/com_dtregister/lib/dtsession.php(137) : eval()'d code on line 1

Warning: Illegal string offset 'Setting' in /home/ralphcas/www/activepeople/administrator/components/com_dtregister/lib/dtsession.php(137) : eval()'d code on line 1

Fatal error: Cannot use string offset as an array in /home/ralphcas/www/activepeople/administrator/components/com_dtregister/lib/dtsession.php(137) : eval()'d code on line 1

Everything else works fine as fair as i can see, since the register is not working...

Any help?
Downgrading did not help as well..

Need the component working again as soon as possible, need it for bussiness.

Webiste is:
http://www.activepeople.ch/kursplan.html

thanks for helping me !