Json Serialization causes a Stack OverFlow Error in Silverlight

Im trying to serialize a shape in Silverlight 4 using Newtonsofts Json serializer. The problem is as soon as I try serialize ANY object, my program breaks and I get the error 开发者_运维知识库

"An unhandled exception of type 'System.StackOverflowException' occurred in System.Windows.dll"

I really don't want to use the .Net one as its overly complicated for such a simple task.