Other mistake: The clock shows the time as 2:20. Ozzie goes outside and spends five minutes talking with Mr. Thornberry. When Ozzie comes back inside, the time on the clock is still 2:20.
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)