Error while packaging app for iOS - Undefined symbols for architecture armv7

First time trying to package an AS3 Air app for development on iOS.

App works fine on Android and is available on the Google/Amazon store etc. The version I'm trying to package has all references to the ANE I use removed to simplify matters.

I'm using Flash Builder 4.7, AIR v4.0 and am developing on a Windows 8 PC.

When using fast packaging no error is thrown but the app just shows a black screen on my test Ipad (v3).

Using standard packaging I get the following error at 57%:

Error occurred while packaging the application:

Undefined symbols for architecture armv7:

  "__Z15abcOP_nullcheckIPN7avmplus6AbcEnvEEvPNS0_9MethodEnvET_", referenced from:

      _abcMethod_builtin_2_2_function public::global21.describeType in AOTBuildOutput-3.o

      _abcMethod_builtin_3_3_function public::global21.describeTraits in AOTBuildOutput-3.o

      _abcMethod_builtin_6_6_function public::global21.describeParams in AOTBuildOutput-3.o

      _abcMethod_builtin_5_5_function public::global21.describeMetadata in AOTBuildOutput-3.o

      _abcMethod_builtin_4_4_function public::global21.finish in AOTBuildOutput-3.o

      _abcMethod_builtin_26_26_function public::Object$._dontEnumPrototype in AOTBuildOutput-3.o

      _abcMethod_builtin_30_30_null ::_init. in AOTBuildOutput-3.o

      ...

ld: symbol(s) not found for architecture armv7

Compilation failed while executing : ld64

Any help you can offer would be very welcome.