Link goes to a bug report in the ipcop-devel board.
IPCop 1.4.20 has trouble installing on computers with USB keyboards - on mine it was sticking at the blue screen just prior to the language selection dialog. Unfortunately many new computer don't come with PS/2 ports, so USB is a must.
If you unplug your USB keyboard after hitting ENTER to start installation it will start properly (minor errors regarding the keyboard will be seen in the boot messages). When you see the language dialog you may plug in the keyboard, wait a few seconds (I press the NumLock to see if the light toggles) then proceed normally.