This is really weird, when did you encounter this error first? Which build are you using?
I just noticed it last night it was the first time I built for the device. I’m using 2013.1203
I’m guessing it’s something wrong with my app because I have other apps that use the set gravity and work just fine. I will try to pinpoint why this is happening though.
What device are you using by the way? ;)
Tried it on a sony xperia play, samsung galaxy note 2 and galaxy s3
Okay then I do not see any other way - check your physics environment (since it seems to be related to gravity/physics) and try to hunt it down 
Good luck!