my virtualbox didn't build the new module and I had to go back and have it build the kernel module for my new kernel.
after running that, it worked fine
did you install virtualbox-ose with the kmod or akmod package. The kmod package doesn't automatically build the new kernel module for you and you have to wait until the update kmod is put into the rpmfusion repo. If you installed the akmod package, then it will build it automatically for you when you update your kernel.