I know you want a fast reply.....but it is frowned upon to DOUBLE POST the same question! soooooo now I get a little bit more information.......Invalid navagation structure.... means that the DVD structure is not Navagational.... cause you might have deleted something that won't allow the DVD to function properly. Are you using DVDRemake? did you rip the movie to the Hard DRive and then got a structure problem? what did you do and how did you do it? what programs and more information would be great!!!!!