Sony DRU-510A Read Error

hello to all

i just purchased the new SONY DRU-510A DVD BURNER

and it seems on some dvds it wont read all the way threw when ripping. for some it will work fine and others it wont read all the way threw when ripping, i was wondering if anyone else experience this problem and if so if anyone has a solution why this happens. the disc that dont seem to read and rip all the way threw r brand new and no scratches or dirty on em. now what i cant understand is when i try and do the dvds that cant seemed to be ripped i tried on my pioneer dvdrom and it reads and rips them just fine, just wont for some reason read and rip from the dvd burner itself

thanks for your time and any help u can give