I am guessing you have a universal host controller interface. Follow your instructions to check in the device manager. If its an open host controller change the /M for /P in the USBASPI.sys line.
Of course having got it booted to DOS you will then need to load the game. You may not be able to get at your HDD but you could load the CD drivers and run the game from CD (or a USB stick..)
Your other option is to try loading the drivers in the command prompt of XP. To do this you would need to edit the file config.nt in your windows\system32 directory in a similar fashion to the config.sys above. I don't think it will work but you may want to give it a try.
You can create an MS-DOS boot diskette from XP by following the info on the link that I gave. This will allow a PC to be booted into a real MS-DOS (version 8 ish) environment. It will not be able to access NTFS partitions though.
Within XP itself, there is a 16 bit emulator and a command prompt (generated by running command.com) that emulates DOS. You can edit the system32\config.nt file to load DOS device drivers into the emulation in the same way that you do with config.sys in real DOS, and many do work. I did point out to molby5 that I doubted the USB driver would work.
I have re-read my earlier post and I cannot see anywhere in it that I claimed there was DOS in XP.