This is a common symptom of a bad burn. Did you burn your disk s-l-o-w < 8X and in a RAW mode, usually listed as DAO, TAO, or SAO? Be sure and verify the md5 sum of the burned drive as well.
Insanity: Doing the same thing over and over and each time expecting a different result.
Democracy is 2 wolves and a lamb voting on the menu. Liberty is an armed lamb protesting the electoral outcome. A Republic negates the need for an armed protest.