I have an HP ProLiant MicroServer N40L (right beside me) running Ubuntu Server 12.04 LTS (64-bit).
I had no issues with install, nor with attempts on 3 other HP MicroServer's (incl. earlier model). I found the USB keyboards (I tried) all worked fine.
I was also able to load 12.04 desktop, with no issues.
For keyboards I have used (all USB): an HP desktop (KU-0316), HP desktop (from d530 PC), Logitech (various), and (current) Good2Better2010 'Sleek Ultra thin Mini Keyboard'. None of these had any issues.
Any issue with wireless keyboards may be due lack of driver (during the install).
Your keyboard may work after install and updates.
Suggest you create a NEW install-USB (maybe under Ubuntu), and try again.
I created the USB-install on Ubuntu 12.04 LTS desktop (using creator tool).
I have had minor issues with mismatched kernels (in the past), when using 11.10 (desktop) to create 12.04 (install), but not recently ..
I suggest a purge and reinstall for your own 'creator' (under 13.04).
It should not be crashing (on startup).