C++: CppLocationGetter not a class, namespace, or enumeration

I'm creating a C++ program that figures out the user's current location. As such, I've created an Objective-C object that will take care of getting the location using CLLocationManager.

I also have a C++ object - called "CppLocationGetter" - that will interface with my Objective-C object. CppLocationGetter.h includes LocationGetter.h (Objective-C), which in turn has an @Class directive for the CppLocationGetter class.
However, in CppLocationGetter.mm, I get an error: "CppLocationGetter not a class, namespace, or enumeration"

CppLocationGetter is within a namespace, but I have a "using namespace" directive before the line where the error is.