Visible crew/equipment: When Doug is working at Cooper's, and goes to get the ladies beer nuts, the camera pans to the left, and a 2nd camera (which is used on the following shot of Doug) is visible on the left side of the screen.
Deconstructing Carrie - S7-E15
Revealing mistake: When Doug flies off the bike and across the screen, in the background is a palm tree, which obviously would not grow in New York. (00:14:20)
Deconstructing Carrie - S7-E15
Continuity mistake: In the kitchen when Arthur says he was a terrible father and gets up, Holly looks over at him with her hand on the edge of the table. She says, "Oh no", but then she's smiling. When the shot changes angle, her arms are crossed. Then Holly says, "Better than my dad, who was too busy chasing the almighty bottle of glue", her hand is instantly on the box of photos again. (00:11:35 - 00:12:05)
Silent Mite - S7-E7
Continuity mistake: In the final scene where Arthur raises his ornament on the Christmas tree, the kitchen door is closed behind him. In the next shot looking out from the kitchen, the door is already open as Arthur walks forward and through it. (00:21:15)
Wish Boned - S7-E17
Audio problem: When Doug found Arthur after his running away and they were about to board the plane to St. Louis, Arthur's voice sounds fuzzy because the new T-shirt he's wearing is covering the microphone on his chest.
Deconstructing Carrie - S7-E15
Visible crew/equipment: When Carrie comes into the house after being hit on by the construction guys, a shadow (boom mic) passes over the TV. (00:12:45)
Silent Mite - S7-E7
Continuity mistake: In the final scene where Arthur takes his ornament from near the bottom of the tree and puts it closer to the top, the door to the kitchen is closed. Then in the next shot from inside the kitchen, the door is already open as Arthur walks towards camera. (00:21:15)
Deconstructing Carrie - S7-E15
Continuity mistake: Doug is sitting on the couch making club music sounds and moving his hands when Carrie reaches out and touches his face to make him stop; then his left hand is instantly on the arm rest. (00:13:10)
Deconstructing Carrie - S7-E15
Continuity mistake: While Carrie was being harassed by the construction workers, Doug was watching by looking out the door to the right. In the next shot, you see Carrie through the window, coming in from the left.
Wish Boned - S7-E17
Visible crew/equipment: When Doug starts to walk over to the flight attendant, a second camera slides into the shot for a few seconds to the right of the screen. (00:12:36)
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.