Head First - S1-E6
Continuity mistake: When the gang walk into Coopers, a woman and man are talking outside on the street. When the camera changes to focus on Arthur a second man has appeared next to the other two and should have been visible in the first shot. (00:03:40)
Continuity mistake: When making a PB&J sandwich, the jar of peanut butter rotates by itself. Note the label. (00:09:30)
Continuity mistake: When Doug falls off his chair his right arm is on the floor in one shot and on the desk part of the chair in the next. (00:09:10)
Continuity mistake: When Doug puts down the remote to grab Carrie's Walkman, the position of the remote changes between shots. (00:00:45)
Food Fight - S4-E13
Continuity mistake: When Arthur tells Doug to eat some salad he is either holding the bowl or not depending on the shot. (00:18:40)
Continuity mistake: When looking at the quote for the repair bill, its position on the table in relation to Kelly's menu is constantly changing. (00:08:40)
Continuity mistake: When Doug says he was reaching for a fig newton, the way Carrie is stood changes between shots. Note her right arm. (00:04:50)
Wild Cards - S2-E20
Factual error: Deacon is holding an In-N-Out drink cup. In-N-Out is a burger chain only located on the West Coast of the United States. (00:02:00)
Revealing mistake: When Doug and the rest are at a ballgame, the man sitting behind them is eating a hot dog. Actually he's pretending to eat, it never shows any bite marks and the guy is pretending to chew it.
Continuity mistake: When arguing about who is going to die first, the amount of whipped cream around Doug's mouth changes instantly. (00:19:20)
Continuity mistake: When talking to Deacon outside, Deacon has his arms folded or straight depending on the camera angle. This is before anyone comes out. (00:08:05)
Hi Def-Jam - S3-E13
Continuity mistake: When Doug is seeing the HD TV for the first time, he's holding his PDA in two hands which then becomes one hand when the camera has changed to a different angle. (00:02:20)
Continuity mistake: When Carrie gets her camera it changes position in her hands before she turns it around. Note the strap, it goes from left to right. (00:06:00)
Continuity mistake: Carrie asks Doug what he's doing when she walks into the bedroom. She then hangs her coat on a hanger and has the coat in her hands (as seen in her reflection in the mirror). Camera changes and she's shutting the wardrobe. (00:08:01)
Answer: Sara hasn't been mentioned in later episodes, and it suggested in later episodes that she never existed, and that Carrie is an only child. Kevin James stated that the producers couldn't think of an good plots to use with Sara, so they left her out.