I'm getting error messages from the semi-official Fallout patch for English speakers. It alternates between "Not enough free hard disk space. Fallout requires at least 20.0 megabytes of free hard disk space." (I got plenty of space...) and "Could not find the master datafile. Please make sure the FALLOUT CD is in the drive and that you are running FALLOUT from the directory you installed it to." The game itself seems to work fine, but I haven't started a new game because I want to get these recommended patches working first. I'm running on Vista.

Extract the files from the patch to Fallout directory and let the new files replace the files already there. You will need to give administrator permission to do this.