Well I'm not gonna look through you logcat right now(might circle back to that, even if it may not contain anything relevant) but I've found that I can make this error message appear by having the camera used by another app(e.g. one that works like a flashlight) and then opening the camera.
So do you use any third party app that make use of the camera? It could be snapchat or Skype for example. If they fail to release the camera when you press the home button, they may be able to cause this problem. If you have such a third party app, try quitting it properly by use of the back button or maybe even force close it.
edit: I'm actually not sure that killing the app will fix the problem, so you may have to try not using it for a while to see if it makes the problem not appear. My bet is that it is caused by skype not releasing the camera properly, since that seems to be the only app accessing it prior to the error.
It can of course also be a hw problem or a low level(kernel) problem. And after looking through the log it doesnt look like the same error i get when the camera is simply occupied. Does it work in a third party camera app after you get the error?