Other mistake: The puppies apparently can't see when Lucky puts his head in front of the TV. The first time we see him do this, he is barely covering anything, but the puppies claim they can't see.
Audio problem: Cruella shows up to buy the puppies. She starts yelling about her pen not working. As she's yelling, her mouth is not moving with what she's saying.
Other mistake: When they are counting the puppies at the end they count the puppies on the stairs. One of the puppies has a red collar, only the original 15 have collars, so this dog is counted twice. So the title of the movie should be 100 dalmatians.
Continuity mistake: When Prissy's owner hears her barking, she pulls her into the house and shuts the window. In the next shot, the window is open again.