Hi,
You can download the hack CD image from here....
http://forum.phathack.com/cgi-bin/yabb2/YaBB.pl?num=1122424315
The file is an ISO image which you can use to create a CD using Nero or similar CD writing program. Note that the CD that you create does not appear to have any files on it when you look at it with Windows Explorer - this is normal. On the CD is a small Linux kernel and the necessary tools to apply the hack to the DMS cartridge for your Phatbox.
Your PC needs to be able to boot from CD - change BIOS settings if needed to enable this. Then pop in the CD and restart your PC - follow the instructions at the above link very carefully.
Although the CD has a Linux kernel on it, you do not need to know Linux at all to be able to use it. Also, it does not do anything to your PC, so that can stay as it is with Windows, etc.
It worked for me (I have a VW box too, but with Volvo firmware installed). A few VW box owners have had problems, but I am not aware that anyone has rendered their box unusable in any way. It is just that for some the hack has not always been as straightforward as the instructions suggest. In most cases there is help on this form should things not turn out right.
Good luck!
Les.