Factual error: After Steve practised changing a baby on the stuffed toy monkey he and Danny leave Michelle's bedroom and walk into the hallway. But the bedroom you see them leaving from when in the hallway would historically be Jesse's bedroom at the time. When they are in Michelle's bedroom in the shot previous to the hallway, the hallway from the bedroom also looks as if they are in Jesse's room based on the view.
Factual error: Aunt Petunia says that the chalice was first seen in the Stone Age, and sends Paul and Barry back to where Stonehenge is just being completed. However, the Stone Age actually ended in around 3300 BC. Stonehenge is believed to have been constructed in around 2500 BC, which was the Bronze Age.