Since the linker is complaining, it means it can't find a function or subroutine (an entry point for a JSB instruction) with the name in your code. The name is an external reference, one which has to be linked in, because it lives in an .olb or .dll file for example.

For example, suppose you had a reference to the api LockWindowUpdate which lives in user32.dll. If you spelled it LockWindowsUpdate you would get this error, because the linker couln't find that name in user32.dll Iy you erroneously told the compiler that the function was in kernel32.dll, you'd see the same error.