Windows phone upgrade to 1.3 problem

I just done the upgrade to 1.3(following http://developer.xamarin.com/guides/cross-platform/macios/updating-xamarin-forms-apps/ guide) stable version, Android and IOS are compiling but WP not, it's showing two errors:

Cannot resolve dependency to assembly 'Xamarin.Forms.Core, Version=1.2.3.0, Culture=neutral, PublicKeyToken=null' because it has not been preloaded. When using the ReflectionOnly APIs, dependent assemblies must be pre-loaded or loaded on demand through the ReflectionOnlyAssemblyResolve event.

Cannot resolve dependency to assembly 'Xamarin.Forms.Core, Version=1.2.3.0, Culture=neutral, PublicKeyToken=null' because it has not been preloaded. When using the ReflectionOnly APIs, dependent assemblies must be pre-loaded or loaded on demand through the ReflectionOnlyAssemblyResolve event.

Any help?