Continuity mistake: In the first scene, where Profion is trying to control the dragon with the green staff, the dragon comes out and we see the backs of Damodar and Profion with the staff raised high above his head. In the next shot, Profion has the staff's top parallel with his head and raises it higher. This is because Profion and Damodar are CGI when the dragon is on-screen in that scene, as you can see in the DVD special features.
Continuity mistake: In the fire chamber scene, the round door is almost shut be the time Willie has got to the half-way point. He then starts to panic. He runs to the end, and that takes about half a minute. The door is now only half-closed. They have obviously opened the door a little bit to allow time for him to get through.