Uwe i'm using this vagcom
http://www.alpha-bid.com/vagusb.html

First, that is not a "vagcom". VAG-COM is software that we make. What this person sells is an interface which he purports to be compatible with our software. Based on what I see at the link you gave, it looks like this interface does not use an FTDI chipset, so I don't have any particular advice for you, other than talk to the guy you bought it from.

-Uwe-