There's a number of things you could be doing wrong.
Did you define MediaClass' methods?
If it's a class from a library, are you linking to the static library?
ihave media2.h which has the class and its member functions..
inside MediaClass.cpp (where that code was) i have #include "media2.h"
im not sure what you mean by linking it?
I changed this.. i had
void InputMedia()
{}
and i changed it to
void MediaClass::InputMedia()
{}