ERROR: Failed to process XAP file - Windows Phone 8 Cordova project

Question

I am having trouble running the Store Test Kit on my Cordova Windows Phone 8 app, using Visual Studio 2013. I can deploy to the device
fine, but when it comes to submitting I get the following error
ERROR - Failed to process XAP file: CordovaAppProj_Release_AnyCPU.xap
I have tried to rebuild the project multiple times, closed and opened the test kit and visual studio but no luck. Looking around the
internet, similar problems were occurring but nothing worked.
I have tried renaming the XAP file created, and even changing its extension to a .zip to find incorrect files that may be causing problems, but nothing.
After rebuilding my project I don't receive an errors of any kind so I am totally stumped!

Answer 1

thanks for your kind reply,
But result is same
PM>  Install-Package System.Spatial -Version 5.6.0
Installing 'System.Spatial 5.6.0'.
You are downloading System.Spatial from Microsoft Corporation, the license agreement to which is available at http://go.microsoft.com/?linkid=9809688. Check the package for additional dependencies, which may come with their own license agreement(s). Your use
of the package and dependencies constitutes your acceptance of their license agreements. If you do not accept the license agreement(s), then delete the relevant components from your device.
Successfully installed 'System.Spatial 5.6.0'.
Adding 'System.Spatial 5.6.0' to Appify.
Uninstalling 'System.Spatial 5.6.0'.
Successfully uninstalled 'System.Spatial 5.6.0'.
Install failed. Rolling back...
Install-Package : Could not install package 'System.Spatial 5.6.0'. You are trying to install this package into a project that targets 'WindowsPhoneApp,Version=v8.1', but the
package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.
At line:1 char:2
+  Install-Package System.Spatial -Version 5.6.0
+  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : NotSpecified: (:) [Install-Package], InvalidOperationException
    + FullyQualifiedErrorId : NuGetCmdletUnhandledException,NuGet.PowerShell.Commands.InstallPackageCommand
Not only this reference, so many other references also not yet ready or not supporting windows phone 8.1 RT apps. 
I am converting windows phone 8 app to windows phone 8.1 RT , for that I need WindowsAzure Storage reference.