SerializationException: Type is not resolved for member "..."

I've been trying to dynamically load an assembly to an AppDomain. I need to do it because I want to call a method dynamically, but don't keep the handle to the DLL while my app is running, so that it can be replaced, if needed. But I'm getting this SerializationException exception: Type is not resolved for member "..." Here's my code: ``` AppDomain domain = AppDomain.CreateDomain("Temp AppDomain", null, AppDomain.CurrentDomain.SetupInformation); try { object obj = domain.CreateInstanceFromAndUnwrap(dllPath, typeName); IMyInterface myObj = (IMyInterface) obj; result = myObj.MyMethod(something); } finally { AppDomain.Unload(domain); } ```