It means what it says. The GPU-accelerated version of the Raytrace 3D stuff only works on nVidia cards. Beyond that it's a moot point - it's an outdated, obsolete feature that never worked well to begin with. 3D text is to be created using Cinema 4D Lite that comes with AE or third-party plug-ins these days. Simply dismiss the warning and forget about the whole nonsense.
Mylenium is right.
The ray-traced renderer will still work on machines without the appropriate NVIDIA GPU's, but it will be prohibitively slow. That being said, the ray-traced renderer is considered obsolete (see here).
We have much more powerful ways of doing 3d in AE these days. See this course for how to use Cinema 4D Lite (that comes included with AE!)
Thank you both for responding, I won't worry about it and use your suggestions instead. Cheers.