I dunno what cause this error.
http://s61.photobucket.com/albums/h53/S ... ent=Da.png
It most likely means that the application is calling for an object (An instance of the object in this case) that doesn't exist. That's my best guess. I would check to see if there might be anything removing it when you start up; perhaps it is too far outside of the layout?
Of course, I could be entirely wrong in every way, but it would be a good place to start.