Well, the "hello world" example that you're trying to build is the C++ one.

The C++ bindings for Gtk+/Hildon are supported by the community (by the Openismus guys), so the hildonmm packages are in the Extras repositories (not installed in the default installation)

Add this line to the /etc/apt/sources.list in scratchbox:
deb http://repository.maemo.org/extras-devel fremantle free non-free

And then, apt-get update, and apt-get install libhildonmm-dev

If you want the default examples (in plain C) are here: https://garage.maemo.org/svn/maemoexamples/trunk/


I know that the one in Forum Nokia is the C++ one, it's a bit confusing because the Hildonmm/Gtkmm isn't supported officially.