Toshiba sd-r6012 1731 Cant get any new dvds to burn. Help!

It used to work withe the older dvd’s, but now with the x4 ones it keeps spitting out blank disks. I updated the firmware from Toshiba and still nothing.

Toshiba sd-r6012 1731 Cant get any new dvds to burn. Help! It used to work withe the older dvd’s, but now with the x4 ones it keeps spitting out blank disks. I updated the firmware from Toshiba and still nothing.