try changing the sata ports of your cd-rom or dvd-rom.. and try again..
like unplugging the sata cable of your cd rom and plug in to a "never-plug in before sata port "
change your dvd rom drive.. and try again..
if u are using PATA drive.. pls do not use Pata in this generation of DP35DP..
recommend to use sata based dvd-rom