Liteon LVW-5005 won't record on any DVD but will on a CD?

Unit will *play* DVDs and CDs just fine but will only *record* on a CD disk now. When I place a blank DVD in I get *failed invalid disk*... It's an all Write unit and I have tried several brands and types of DVD-R/DVD+R/RW but nothing works...

*Any* ideas would be very helpful...