dvd decrypter and dvd-rw

[blackbear]

When i use decrypter for burning an image on to a dvd-rw it comes up with the disc if full, which is fine. It then asks do you want to use decrypter to erase the disc. i hit yes. It will erase it but when it goes to write i get an I/O error.
the error is invalid field in CDB. It ten says failed to reseve track. i have wasted 3 -rw's. any idea what is causing this??