Why am I getting this error exporting to win 8 store?

  I just got a windows 8.1 computer.  I have the latest free version of unity.  I downloaded the windows 8 SDK from MSDN and got the free 2013 visual studio express update 3. When I try to export out the game to windows 8 store, I get the error below. It will not compile. I can export out to android, windows 7 and such, just not to windows 8 or 8.1.

  The setting for windows store are as follows (although I have tried different settings). Type C++ SDK 8.0 dev build: off

  I tried uninstalling VS 2013 express for desktop and reinstalling it. VS seems to work. When I run it, it comes up with a start screen (I've never used it before). I also tried installing the standalone SDK. 

  This is the link to my manual download and install of the SDK. I tried this. I assume this is the correct SDK.

http://msdn.microsoft.com/en-us/windows/desktop/hh852363.aspx

  I also download this link of visual studio. I clicked the first option "Microsoft Visual Studio Express 2013 with Update 3 for Windows Desktop - English"

http://www.visualstudio.com/en-us/downloads#d-express-windows-desktop

I also tried uninstalling everything, installing sdk8, then installing unity. Still, it give the error. It's like it can't find the windows 8 SDK or something. ------------- Could not start compilationException: 'References\CommonConfiguration\Neutral\Windows.winmd' not found, do you have Windows 8.0 SDK installed? UnityEditor.Scripting.Compilers.MicrosoftCSharpCompiler.FillNETCoreCompilerOptions (MetroSDK metroSDK, System.Collections.Generic.List`1 arguments, System.String& argsPrefix) (at C:/BuildAgent/work/d63dfc6385190b60/Editor/Mono/Scripting/Compilers/MicrosoftCSharpCompiler.cs:134) UnityEditor.Scripting.Compilers.MicrosoftCSharpCompiler.StartCompiler () (at C:/BuildAgent/work/d63dfc6385190b60/Editor/Mono/Scripting/Compilers/MicrosoftCSharpCompiler.cs:225) UnityEditor.Scripting.Compilers.ScriptCompilerBase.BeginCompiling () (at C:/BuildAgent/work/d63dfc6385190b60/Editor/Mono/Scripting/Compilers/ScriptCompilerBase.cs:60) UnityEditor.HostView:OnGUI()