Continuity mistake: When Red and Eric were talking in the driveway there was a van right next to them. The tail lights shown on that particular model were only produced in the mid 80's and later.
Visible crew/equipment: As Donna plays footsie with Eric in the car while driving up to Jackie's ski lodge, a crew member's arm can be seen in the backseat. (00:05:17)
Answer: It's Ashton Kutcher's dog.