When Nick is talking to Ernest as they are picking out a box of chocolates and some flowers, the box that Ernest picks out is alot bigger than the one that Nick gives Beth in her office just minutes later.
Nick is visiting at Beth's house in the evening. To decorate the tree, he has to go to the garage to get the ornaments. When he gets there, it is daylight.
When Beth is consoling Holly on the carriage after the actor playing Santa complains about the child actress and storms off, Holly has "snow" flakes in her hair, seen from the back. One camera cut later, same scene, all the snowflakes are now gone from the girl's hair.
Nick says that in Germany, they call him Kris Kringle. This is untrue, because Kris Kringle comes from ChristKindl, meaning Christ child. In Germany, he would be known as der Weihnachtsmann.