Or, of course,
this computer needs a keyboard to operate, so until
you find a
keyboard, plug it in and
press F1, you cannot
continue.
The really idiotic thing about the message is that it is not needed, and indeed harmful. I can think of many situations where you do not need a keyboard (e.g. a server locked away in some cupboard, or any MS-DOS computer with an AUTOEXEC.BAT file, or (probably) even a Windows "computer" with some not-too-difficult configuration). Why not leave it to the operating system to decide if it refuses to continue without a keyboard?
The BIOS (which issues this message) simply doesn't have enough information to make a call on this matter! If you don't have enough information to decide, the logical thing is to pass the buck!