Other mistake: When David takes a book from the bookshelf and opens it, a small piece of paper falls to the floor. Neither he, Ozzie nor Harriet notices it.
Other mistake: Ozzie has just brought the mail in. He says, "Here's a bill. Here's another bill." Instead of looking at the rest of the mail, he hands it to Harriet, telling her, "I've had enough bills for one morning." The time on the clock is 4:15.
Rover Boys - S1-E18
Other mistake: David's teacher is called Mrs. Fraser in some scenes and Miss Fraser in other scenes.
Other mistake: Cathy Calhoun is knitting a pair of socks for her brother, and offers to make a pair for Ozzie. She tells him, "If you really like them, I could get some more of the material." Knitting is done with yarn, not material. (00:06:50)