Errors when updating AIR SDK in Flash Pro CS6

So I've been developing an app in AIR 3.4 (I know... so old right?) for quite some time now and still cant update to even 20 because of this. I've downloaded the latest SDK and linked it with the CS6 menu: Help>Manage AIR SDK. Of course then I select the "publish target" to AIR v20. Then when I compile, I get a whole bunch of runtime errors from my code referring the stage (ie: stage.stageHeight)... This is killing me!!

Error #1009: Cannot access a property or method of a null object reference.

at Main()

TypeError: Error #1009: Cannot access a property or method of a null object reference.

  at Main/startOrientationChange()

Line 255 in Main.as: stage.autoOrients = true;

Line 1991 in Main.as: stage.addEventListener(Event.RESIZE, orientationChanged);

And a blank app with what looks like the default Preloader SWF...

Any help is appreciated!

-Nick