If you are on Windows, download transmac and open the iso with it, go to /system/library/extensions and drag & drop your Kext, close and reburn...boot with -f -v, if you have a success install, copy the kext again ( leo HD /system/library/extensions ) boot with -s and type :

mount -uw /

cd /system/library/extensions

chmod -R 755 "yourkext.kext"
chown -R root:wheel "yourkext.kext"
reboot

boot with -f