Problems: "disc is dirty" and scratches on dvds

hello… i used conedvd to try to copy happy potter and the gobley of fire and it copied on the computer but when i put it into the dvd player and it says “disc is dirty” why? how can i make it copy so my dvd reader and my computer will play it??? it will not play.

also, how do i copy the dic if ther are scrates on it? clonedvd wont copy it? what can i do??

i tried to use dvd shrink and that did not work on eather movies. is there a program that can ignore scratches?

why cant i make a copy of the harry potter dvd that will play?

thank you