Hi Juan,
You're right; that message does mean the FPGA image is incompatible with your UHD installation. You'll want to run the uhd_images_downloader that came with your GNURadio installation. That should overwrite the images stored on your host to a set of images that are compatible with the version of UHD you're running.
What do you mean you reinstalled UHD? Could you give us the commands you used to install GNURadio and UHD (if they were separate steps)? If you used a package manager, GNURadio should come with an installation of UHD, which GNURadio is linked against.
Regards,
Brent