Flash Player 9r45 Compatibility

So I’ve been building a relatively large AS3 application which runs perfectly fine on Flash Player 9r45. However, if I run it in Flash Player 9r28 or anything less, it simply doesn’t work. It’s very strange but it seems like as soon as I call a function on any class (i.e. preloader), the Flash just… stops…

It’s very difficult to debug, and I’ve been using this firefox extension to switch flash versions.

I took a look at the version changes, and I’m pretty sure my flash isn’t encountering any of the following problems…
[LIST]
[]New ActionScript 3.0 components for Flash CS3 Professional do not function correctly in versions prior to Flash Player 9.0.45.0.
[
]Runtime Shared Libraries (RSLs) exported for ActionScript 3.0 generate a runtime security error. (195395)
[]Display objects instantiated by the playhead entering a frame because of a gotoAndStop command (or similar action) incorrectly process actions on frame one. (189490)
[
]flash.text.TextField.getCharBoundaries returns a rectangle that is offset to the left by 2 pixels for fields that are created using the Flash CS3 Professional text tool. (193249)[/LIST]Although I am not 100% what the Display objects instantiated by the playhead entering a frame because of a gotoAndStop command (or similar action) incorrectly process actions on frame one means…

Any help? Any ideas?

Thanks,
-Danny