4.12.1 Compile issue with mobile

I have a mobile app (on all the major app stores) that was compiled with
4.10.0 FP 11.8 Air 3.8, but, I just installed 4.12.1, took all the options
using the Apache Flex SDK Installer, but, whenever I use this SDK, I now get
error about ActionScriptSKinBase not defined. I can run just a simple
mobile projects (New...,Mobile Project) using this SDK, but, can't get my
previously working mobile app to compile using the new SDK.

Anyone else run into this issue? Full stack trace below.

ReferenceError: Error #1065: Variable spark.skins::ActionScriptSkinBase is
not defined.
at
global$init()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/mobiletheme/src/spark/skins/mobile/SkinnableContainerSkin.as:34]
at Function/<anonymous>()
at
mx.styles::CSSStyleDeclaration/http://www.adobe.com/2006/flex/mx/internal::addDefaultStyleToProtoChain()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/styles/CSSStyleDeclaration.as:974]
at
mx.styles::CSSStyleDeclaration/http://www.adobe.com/2006/flex/mx/internal::addStyleToProtoChain()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/styles/CSSStyleDeclaration.as:904]
at
mx.styles::StyleProtoChain$/initProtoChain()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/styles/StyleProtoChain.as:258]
at
mx.core::UIComponent/http://www.adobe.com/2006/flex/mx/internal::initProtoChain()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/core/UIComponent.as:11458]
at
mx.core::UIComponent/regenerateStyleCache()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/core/UIComponent.as:11521]
at
mx.managers.systemClasses::ChildManager/addingChild()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/managers/systemClasses/ChildManager.as:168]
at
mx.managers.systemClasses::ChildManager/initializeTopLevelWindow()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/managers/systemClasses/ChildManager.as:360]
at
mx.managers::SystemManager/initializeTopLevelWindow()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/managers/SystemManager.as:3065]
at
mx.managers::SystemManager/http://www.adobe.com/2006/flex/mx/internal::kickOff()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/managers/SystemManager.as:2851]
at
mx.managers::SystemManager/http://www.adobe.com/2006/flex/mx/internal::preloader_completeHandler()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/managers/SystemManager.as:2731]
at flash.events::EventDispatcher/dispatchEventFunction()
at flash.events::EventDispatcher/dispatchEvent()
at
mx.preloaders::Preloader/timerHandler()[/Users/aharui/flex-sdk-4.12.1/frameworks/projects/framework/src/mx/preloaders/Preloader.as:572]
at flash.utils::Timer/_timerDispatch()
at flash.utils::Timer/tick()