Mr. Bevis slides down the banisters in the middle of the hallway, yet he rolls out of the right hand door. In reality, his roll should have been stopped by the closed left hand door.
The little boy is right in the doorway when Mr. Bevis falls down the stairs, but when the camera pans out to a wider shot, the little boy isn't in the doorway.
Obvious stunt double for Mr. Bevis when he falls coming out the front door and tumbling down the front steps after sliding down the banister.
The light pole shakes when the monkey climbs up it and the light fixture on top nearly falls off.
When Mr. Bevis asks Mr. Hempstead, "Who might you be?", Mr. Hempstead corrects him, saying "Whom; objective case". That is, in fact, wrong, as 'Who' is used as a predicate nominative and, therefore, the nominative case is correct.
A kid pushing Bevis's car looks toward the camera as a cue.
While Mr. Hempstead is trying to impress Mr. Bevis, one of the things he mentions is that he helped Ben Hur win his famous chariot race. This would have been impossible since Ben Hur is a fictional character (created by General Lew Wallace in the mid-1800s) and not an actual person from history.