There seems to be an issue with passing generic arguments when attempting to create a parametrized instance with Castle Windsor
Your SandCoordinator<T> depends on IGenericManager<T>, not GenericManager<T>.
When you're putting a value in Arguments that you want Windsor to use as something else than its concrete type you have to be explicit about it.
new Arguments { { typeof(IGenericManager<Simpleton>), runtimeConstructorParam } };