Compiling to iOS in Flash Builder throws Java null exception

I'm attempting to port a large application from the browser to iPad. It works perfectly fine when I do a 'fast' compile, but when I attempt to compile using the 'slow' packager I get this error:

Error occurred while packaging the application:

    Exception in thread "main" java.lang.NullPointerException

        at adobe.abc.Nsset.match(Nsset.java:263)

        at adobe.abc.Name.match(Name.java:555)

        at adobe.abc.Symtab.getEntry(Symtab.java:37)

        at adobe.abc.Symtab.get(Symtab.java:55)

        at adobe.abc.Type.setNeedsArgumentsUpInheritanceHierarchy(Type.java:343)

        at adobe.abc.Type.setNeedsArgumentsUptoRoot(Type.java:269)

        at adobe.abc.GlobalOptimizer$InputAbc.resolveType(GlobalOptimizer.java:5 58)

        at adobe.abc.GlobalOptimizer$InputAbc.resolveType(GlobalOptimizer.java:4 48)

        at adobe.abc.LLVMEmitter.generateBitcode(LLVMEmitter.java:327)

        at com.adobe.air.ipa.AOTCompiler.convertAbcToLlvmBitcodeImpl(AOTCompiler .java:472)

        at com.adobe.air.ipa.BitcodeGenerator.main(BitcodeGenerator.java:82)

    Compilation failed while executing : ADT

I see one other thread where this is addressed but unresolved. Can you direct me as to how to resolve the issue?