When i tried to burn a cd on my asus quietrack cdrw drive, it got spoilt and wouldn't even read anything. It had to be sent to the company for repair. This also happened on another gentoo user's asus cd writer. Please check the device driver for asus devices. Reproducible: Didn't try Steps to Reproduce: 1. 2. 3.
I know people using Asus cd writers on Gentoo. Not much I can do here, sorry. Have you tried contacting asus?