CloneDVD 2: Please insert recordable disc Dual Layer help

When I try to write .vob/.ifo files with CloneDVD 2.0.9.4 to a blank DVD+R DL, it doesn’t recognize that the blank DVD is in the drive. I’m using Memorex DVD+R DL, and my dvd writer is a PBDS DVD±RW DS-8W1P ATA Device with it’s latest driver update. I’m using windows vista.