Oh well, it seems I get the error only under Virtuabox (which is version 5.1.4). I just burn a CD with that nova.iso, and after showing fast invalid hints messages, goes to the not handled by monitor video mode. This is the same computer I tried under VirtualBox (Debian 4.6.0-1-amd64, Celeron D, 2Go).
A bit to my own surprise, VirtualBox does not give much option for the simulated CPU.