Revealing mistake: Towards the middle of the movie Fats has a motorbike accident and is seen riding into a huge rock. When the stuntman actually hits the rock and goes ballistic there are huge piles of straw right next to the rock that hadn't been there before. In the course of the event the stone gets shifted by about a metre, thus revealing itself as a prop.
Continuity mistake: On his way to Sun City Mr. Bones relieves an elephant from his constipation by extracting some blockage through the rectum. This results in a huge elephant pat flying with great momentum horizontally in the direction of a bystanding lady's backhead. Then the lady is shown from behind, running away, and the pat, which made a rather sticky impression when it hit her, is gone.