QNX Momentics: GoogleMock - Return has value, in function returning void error

I need to write mock methods for a class, provided to us by a third party supplier. The class, that I need to mock has virtual methods and I am mocking them in my mock class.

This is the original class:

    class Derived : public Base
{

public:
    virtual void addResource(const Resource& resource, std::string resourceURL);
    virtual void removeResource(const Resource& resource);
...
};

Just to let you know, these two methods are virtual in the Base class, too.

This is the Mock class:

class MockDerived : public Derived {
 public:
     MockDerived (std::string name);

  MOCK_METHOD2(addResource,
      void(const Resource& resource, std::string resourceURL));

  MOCK_METHOD1(removeResource,
      void(const Resource& resource));
};

All this works fine. I am executing tests without a problem. However, in QNX Momentics (The QNX version is 7.0), which is really just Eclipse, it gives me the following error:

Return has value, in function returning void

Anybody has an idea what I need to do in order to remove the errors. It still works, but it is annoying to have this error and who knows what can go wrong in the future.