• The organ has only white keys and not black ones. Also, I'm not sure the F E E D notes are keys right next to each other.
• Both the washing machine and the fan are wireless (battery operated?)
• Scooby & Shaggy are chasing the ghosts, who slide down the stairway. How do they get down to catch them and before the ghosts can get to the bottom of the stairs?

I don't mean to pick on the makers of my favourite cartoon in finding errors though. :)