I got an very strange problem.
After I “Build and Go” my application, I ran this app in my iPhone device. There had a problem that app quit without automatically. But everything is Ok in Editor.
Absolutely no null-pointer. Everything was running normally in Editor.
I think my screen is not heavy, just a simply game. It was fine before I changed the GUISkin, I added a new customer GUIStyle. But I back to none customer GUIStyle, the app still jump out.
There may be better ways to find the problem, but what I would do is make a copy of your project, and then start disabling/deleting stuff until it works again.