If you do not have Linux on your system and can not install it for the moment, get yourself a Linux Live CD, such as the Ubuntu Desktop CD: http://www.ubuntu.com/getubuntu/download A Linux Live CD will not alter your existing Windows (or whatever) installation.
A Ubuntu Live CD can be downloaded for free (see above) and burned on a CD from within Windows XP. No additional software is required.
Start Ubuntu from the CD, download the files (dfu-util, rootfs, kernel) as described into /tmp
Make dfu-util executable by "chmod +x ./dfu-util" and then flash the kernel and rootfs like described, but make sure that you execute dfu-util as root, putting "sudo" in front of dfu-util does the trick ("sudo ./dfu-util ...").
If you need to do a nand erase and connect to uboot via tty, you need to install cu. To install cu on a Ubunto Live CD, go to add programs, select advanced, select communications and cu is the first entry. You can also do a "sudo apt-get install cu" to install from command prompt. The installation will work, even though its just a Live CD. Of course, if you reboot from the Live CD, you will have to install again.