I'm not clear why anyone would still fool with Knoppix STD, much less try to install it. It was released 6 1/2 years ago, has never been updated, and Wikipedia kindly calls it "stagnated, lacking updated drivers and packages". If what you are looking for is a security based distro, I would suggest that you consider a different distro. A current version of BackTrack would be one that I could recommend. although there are others. Don't waste your time with STD.