Fatal Error on Access of Layout Settings

Whenever I create a panel page and go to the layout settings page I am greated with the message:
Fatal error: Unsupported operand types in W:\www\drupal\sites\all\modules\panels\includes\display_edit.inc on line 517
I have no idea why this could be but beta 3 worked fine.

I have tried uninstalling panels and starting from scratch (with the module not the site) but this error keeps rearing its ugly head everytime I access that page.