so can you just clarify what you want to do with the USB to parallel port adapter?
is there a USB port on your calculator which you want to plug it in to?
if this is your plan then no, it won't work. the calculator's USB port (if it has one) will only be a USB device port. as the USB to parallel port adapter is also a USB device you wouldn't be able to connect the 2 together.
one of the devices in USB communications must be a USB host, for example a PC.
if on the other hand you intend to use the USB to parallel port adapter on a computer and controll your bot from your computer then yes, this can work.
on some operating systems you can controll the pins on a parallell port independently allowing you to controll up to 12 output pins with only very simple circuitry.
i know this works under DOS, Linux and easily versions of Windows but i think i read somewhere it doesn't work under XP...
as for how to write the software, i can't remember the exact command but it's 1 line in a C program running on your PC to change the pin's voltage. you'd have to research that bit yourself.