Continuity mistake: After Sarah has called at Harry's office, Harry prepares to open his office door to see her out. The camera cuts back to Sarah for a moment, then back to the camera angle on Harry as she walks to the door. In that short space of time, the sliding cupboard doors have changed their configuration, and the blinds in the upper left of the frame have partially closed. (00:18:45)
Continuity mistake: In the very beginning, when the nun puts the baby in the crib, she puts a blanket on him he pushes it down to his feet, then the camera goes to the nun walking out of the room, and when we see the baby again the blanket is covering him again. (00:04:25)
Continuity mistake: In the scene when John Ritter is trying to fire Santa and the elf, there is a cup with candy canes on the edge of his desk. The number of candy canes change with each shot. (00:32:20 - 00:34:10)