Works great with flash player but gives error with iphone

When I use the flash player to test my file it works great. But when I use the iphone OS it gives me these problems. I've looked up a lot of the related error problems and haven't found the answer. Any ideas?

TypeError: Error #1009: Cannot access a property or method of a null object reference.
    at timerCreation3_fla::MainTimeline/frame3()[timerCreation3_fla.MainTimeline::frame3:3]
    at flash.display::Sprite/constructChildren()
    at flash.display::Sprite()
    at flash.display::MovieClip()
    at flash.display::MovieClip/nextFrame()
    at timerCreation3_fla::MainTimeline/forwardRoll()[timerCreation3_fla.MainTimeline::frame2:23]