Character mistake: Rob is having a nightmare, part of which involves the disappearance of his thumbs. When he finds Laura at home, the script calls for him to say, "I want you to help me get my thumbs back," but he actually says, "I want you to help me get my thumb backs."
Plot hole: In the episode "That's my Boy" when they bring Richie home from the hospital, Rob and Laura are living in the house they have for every show. However, in the episode "Where did I come from" when Laura went in to labor, they lived in a different house. They couldn't have moved while Laura was in the hospital.
Factual error: When Laura and Sally are about to go to the bedroom, Buddy and Rob are going to sleep in the living room of the haunted cabin. Rob and Laura tell Buddy and Sally things like how he steals the pillow and he takes all the covers at home. However at home, they sleep in twin beds so they shouldn't know such things. This is true. However, they do have a son. They had to share a bed at least once in their marriage.
Continuity mistake: In this episode it is shown that the Petries live in a house with a huge rock in the basement. In the episode where Buddy's brother visits (Hustling the Hustler), they play pool in the basement and there is no rock.