Actually, if the driver causes the error, and it isn't seen at the printer, you could staop the printer from seeing the toner is empty by disabling SNMP possibly. (It's worth a shot)
Then I have nothing more to provide, try calling Xerox, I can print but obviously I don't have any empty toners in mine, so it means nothing.
The only thing you should have to do driver side is choose Black.
It may not work with an Empty toner, so try a copy in BW to verify if you have a printer problem or an intentional by Xerox device stop.
If it works on copy, it may be that you have an App sending color. Acrobat/Reader certainly does because by default, it outputs to print in RGB, so you need to modify how it handles the output.
File > Print > Advanced > Let Printer determine color
With that selected, if the printer supports BW print when color is empty it should work.
