I think that this scene from 'Subject 13' is important.
As Walter throws the paper crane into the air and continues to tell his story it appears to flap its wings for a brief second and then ignite. I think that this was much more than cheap parlor tricks, I believe that Olivia is following the verbal cues from Walter's story and subconsciously using her telekinetic and pyrokinetic powers to both fly the crane and then subsequently ignite it. This would be clever psychological manipulation and control of Oliva's gifts by appealing to her imagination through story telling. She imagines it, and then it happens. This would also serve as evidence that Walter and Olivia were already very familiar with her pyrokinetic abilities which would mean that this episode is not at all inconsistent with findings from the video tape uncovered in the episode 'Jacksonville' (in the videotape from Jacksonville we see a very scared very young Olivia curled up in a corner after lighting part of a room on fire, in this tape we hear Bell's voice because Bell is apparently in the room).
Some have suggested that the scene from 'Subject 13' in which Olivia lights the room on fire and the scene from the video tape in the episode 'Jacksonville' contradict each other. I don't think they contradict each other at all because they are two completely different events.