Cycling redundancy check error

hello everyone. i have a plextor px-708A dvd burner and samsung dvd-rom sd-616E. i usually back up a lot of movies and i have had any problem before. however, yesterday i tried to decrypt a dvd with dvd decrypter using the plextor drive and it gave this error: “I/O Error, L-EC uncorrectable error”. then i tried to do the same thing with my samsung drive and it gave me another error: “unrecovered read error”. Afterwards, i used dvd shrink to decrypt the dvd using both the plextor and the samsung drive and the following error appeard: “cycling Redundancy check”. I don’t know what is going on and i don’t understand any of the errors. i don’t really know what to do. i hope someone can help me. thanks

p.d. my pc is a dell 4600, intel pentium 4 cpu 2.80 ghz, 256 mb ram
i also tried to decrypt with three different dvds.

It’s your media try better media. I had that problem and was the media

but i wasnt even burning. it shows me the error when the drivers are reading the dvd i want to copy later.