It means what it says - the 3D tracker has to be used in the comp, not the footage source view. Of course none of it matters. As per your screenshot, there is nothing trackable in your graphic. It seems you are completely misunderstanding the process, but since you have not provided any details about your actual setup nor a link to the tutorial you are following we honestly can't have a clue where you may be going wrong. That aside it's always a good idea to at least glance over the online help to get a basic understanding of how AE works, especially when such advanced workflows are involved.
If you are carefully following a tutorial and it is not working at all then you are probably following a tutorial prepared by an enthusiast that does not really know what they are doing or how to properly explain the workflow. Please embed your screenshots using the toolbar. It's a real pain to have to follow the links.
I am with Mylenium on this one. That is a graphic, not footage from a camera, so there is no reason to use the Camera Tracker. Cropped screenshots are also not useful when diagnosing a problem. We need workflow details, design goals, and screenshots that show us what you have tried to do with the layers. When you have problems with a tutorial we need to know which tutorial you are trying to use.