Here’s a possible solution I found in a local forum and works for me (English WinXP, used with another language). Portmac was right, the problem is with VSO’s Patin-Couffin that won’t install properly.
But the solution is more simplier (and lame)
Uninstall all DVDFab.
Go to Control Panel, Regional and Language Options, and set Standard and Formats to “English (United States)” (or whatever it is in your language)
Set your regional settings back
This way Patin-Couffin should install properly. That means a working DVDFab for you.
(First, I tried this method on VSO’s latest Blindwrite5 that had also failed to install Patin-Couffin before. It comes with a handy driver (Patin-Couffin) installer/checker/uninstaller tool that can be used even when the main application is already installed)