Δώσε αυτό και λογικά θα είσαι οκ

su -c 'yum localinstall --nogpgcheckhttp://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-18.noarch.rpmhttp://download1.rpmfusion.org/nonfree/fedora/rpmfusion-nonfree-release-18.noarch.rpm'