[flexcoders] Error #1009: Property or Mehtod of a null object reference

[scowling_beer]

Hello All,

Firstly I understand what causes the #1009 error.

What I am having trouble with is reproducing it in my flex development
environment.

I have an application that calls custom components into a ViewStack.
When the user changes sections within the viewstack it fires an event
which calls a public method called saveSection within the custom
component - the section they just left.

When debugged and run within my Flex dev environment it works fine,
until I deploy it to another development machine. It's then that I get
the Error 1009.

This is driving me crazy. This code has previously worked fine.

I'm happy to post some pseudo code or examples if needed, but generally
I'm after advice. If I am viewing the component called into the
viewstack... how can it be null? Complicating this is that the same code
called for the other sections works as expected!

The creationPolicy on the viewstack is "all"

MainApp
   {changeSectionHandler -> oldSection.saveSection()}
  ViewStack
      SectionA
        {saveSection()}
      SectionB
        {saveSection()}
      SectionC
        {saveSection()}


Any help appreciated.

Cheers
Steve