My guess is that it's tied into electricity and perhaps the original button pushing. Something about electricity put Jacob into his current state (dimension shift? he's there but out of phase?... I hope not because that is standard sci fi stuff that's been explored to death already). Anyway, the flashlight -- i.e. use of electricity -- triggered all kinds of craziness. I think it's not because Jacob doesn't "like" technology but because his state, whatever it is, does not react well to electric fields, even small flashlight-sized ones.

What's even weirder is that it looked like the knocked over lantern set the place on fire, but when they went outside, not only did the cabin not go up in flames, it seemed to re-set to normal. I was waiting for Locke (aka bull in a china shop) to blow up yet another valuable, information-containing site.

You really need to put your breakables up on a high shelf when John Locke comes over for tea.