has to be a program error, because they do save, perhaps if you find the file that saves these settings delete it, doom should recreat it and then perhaps it'll keep em, other a reinstall is in order, or perhaps someone, anyone wiser than me (wont be hard), can help.
Yes it is. I doubt it's the config file though, It's a fresh install of the game. He's recently formatted and re-installed XP SP2, and installed Doom3 whilst I was there. It just seems to be temperamental, it remembered the settings once out of about 8 or so launches of the game.
Also, when you are exiting the game be sure you are leaving the by hitting Exit.. blah blah. With some games if you make options changes and leave the game by non standard methods (typing quit or exit in console for example) they dont save changes. Or atleast this has been my experience.