3D Film Side-Effects - Cloverfield & U2 3D Cause Vertigo
There was a similar problem with the original Blair Witch movie. Signs were posted at the theater I saw it in warning of people getting sick. The assumption by many seemed to be that it was due to the movie being scary, not the camerawork. They were wrong.
A similar malady affects people playing first person shooter type games as well, especially on big screen TVs where it's even more immersive. Also pilots who spend a lot of time in simulators. The visual cues of motion don't match the lack of motion reported by the inner ear and our brains get confused.