#10 instructions worked just fine on kernel version 3.8.0.5. If your /opt/VBoxGuestAdditions-4.2.6/src/vboxguest-4.2.6/vboxguest/VBoxGuest-linux.c is empty, try installing first without making any changes. Once the compilation fails, you can try again. Also, please make sure to install guest addition drivers from the downloaded iso file and not from Ubuntu's repository. It has the old version 4.1.2.
#10 instructions worked just fine on kernel version 3.8.0.5. If your /opt/VBoxGuestA dditions- 4.2.6/src/ vboxguest- 4.2.6/vboxguest /VBoxGuest- linux.c is empty, try installing first without making any changes. Once the compilation fails, you can try again. Also, please make sure to install guest addition drivers from the downloaded iso file and not from Ubuntu's repository. It has the old version 4.1.2.