JSON C# problem using Newtonsoft

Trying to compile a project using the Newtonsoft.Json.WindowsPhone reference and I am get开发者_如何学运维tign 2 errors when building. I am compiling for windows mobile 6.0 and the latest version of Newtonsoft ver 4.0 and I don't have a reference to System.Windows available to select and System is already referenced. Any ideas on how to fix this?

 The type 'System.Collections.Specialized.INotifyCollectionChanged' is defined in an assembly that is not referenced. You must add a reference to assembly 'System.Windows, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'

 The type 'System.ComponentModel.INotifyPropertyChanged' is defined in an assembly that is not referenced. You must add a reference to assembly 'System, Version=2.0.5.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e'.

Okay found the answer by downloading the 3.5 version of the Newtonsoft and using the Compact version, Newtonsoft.Json.Compact.dll.