The path to ditaa.jar seems to have changed.


Debugger entered--Lisp error: (error "Could not find ditaa.jar at
  /home/sebastian/emacs/lisp/ext/org-mode/scripts/ditaa.jar") 
  signal(error ("Could not find ditaa.jar at
  /home/sebastian/emacs/lisp/ext/org-mode/scripts/ditaa.jar")) 
....


This patch fixes it: