I experienced a similar problem which didn't allow me to do a 13.10 server install. I believe that this bug report may be related to your problem
The fix given in the bug report, you will need some kind of keyboard or input device, suggests enable the saucy-proposed repository, open
sudo nano /etc/apt/sources.list
Now add this to the end of the file
deb http://archive.ubuntu.com/ubuntu/ saucy-proposed restricted main multiverse universe
Now now install
sudo apt-get install initramfs-tools
and update initramfs
sudo update-initramfs -u
Finally reboot for the kernel changes to be applied
sudo reboot
This will install initramfs-tools
and initramfs-tools-bin
version 0.103ubuntu1.1
and your keyboard should work.