Can't create or edit thread after upgrade from 1.8.18 to 1.8.19

[find-us.dk]

Hi 

After i have upgraded from 1.8.18 to 1.8.19  am i not able to create or edit thread.
It just says: The website cannot display the page (See attachement)

   

Kind Regards 
Stephan Wagner

www.solarsikring.dk