This has caught me out a couple of times now. I was getting this exception:
Castle.MicroKernel.ComponentActivator.ComponentActivatorException: ComponentActivator: could not instantiate MyNameSpace.ClassName ---> System.ArgumentNullException: Value cannot be null. Parameter name: types at System.Type.GetConstructor(BindingFlags bindingAttr, Binder binder, Type types, ParameterModifier modifiers) at Castle.MicroKernel.ComponentActivator.DefaultComponentActivator.FastCreateInstance(Type implType, Object arguments, Type s
The exception could be a bit more informative - it turns out this is caused by not providing a public constructor on the class (it was accidentally set to ‘protected’).