Need Help with LH-20A1H?

I just bought a Liteon model LH-20A1H dvd+r dl. I tried burning some media usgin nero 7 onto a dvd+r. But there is nothing burning to the disc, the lightscibe is burning just fine on the dvd+r. When I try using a dvd+rw to burn my media, it is working fine. Why can’t I burn on the dvd+r but can burn on the dvd+rw when my dvd burner supports both??? Please help

What brand of media is the DVD+R?