Randomly stopping animation

Question

I'm working on an animation project using the standard "Rain" preset ActionScript. The animation works in the scene I need it, to up to about the 50th frame in. Then, the rain animation stops mid-fall and I get this error message:
TypeError: Error #1009: Cannot access a property or method of a null object reference.
          at rain1_Scene3_fla::MainTimeline/randomInterval()[rain1_Scene3_fla.MainTimeline::frame1:42]
          at Function/http://adobe.com/AS3/2006/builtin::apply()
          at SetIntervalTimer/onTimer()
          at flash.utils::Timer/_timerDispatch()
          at flash.utils::Timer/tick()
Preferably, I'd like the rain effect to continue throughout the entirety of every scene, but just getting through this one would be fine. If it would.
I know next to nothing about ActionScript, so the more dumbed-down the answer, the better. Haha.
Thank you so much.

Answer 1

In frame 1 line 42 whatever object your code is trying to target does not exist (as far as the code in frame 1 sees it)...
The 1009 error indicates that one of the objects being targeted by your code is out of scope.  This could mean that the object....
- is declared but not instantiated
- doesn't have an instance name (or the instance name is mispelled)
- does not exist in the frame where that code is trying to talk to it
- is animated into place but is not assigned instance names in every keyframe for it
- is one of two or more consecutive keyframes of the same objects with no name assigned in the preceding frame(s).