DBP comes with a different physics engine, ODE. It isn't supported and doesn't do a fraction of what Dark Physics does. But, if your physics needs are minimal, ODE can do the job for you. I believe that the problem is creating a rigid body that isn't a box or sphere. I don't find this to be a bad limitation at all, most objects can be represented as boxes to great effect.
Dark Physics does not come with Dark Basic Pro. You have to buy DBP and Dark Physics. It is a plugin.
Did you watch the videos? Game physics really is amazing, I love Dark Physics and will incorporate it into every project I do from now on. The best part is that it's a million dollar SDK that we get to use for free (after purchasing the plugin, of course). Can't beat that.
Come see the WIP!