Help with Burning Leopard Single Layer Disc, Problems With Burning it On RW DVD-Help

Hello, first time post. I have a compact single layer DVD .dmg file of Leopard 10.6. Upgrading from Mac OS X 10.4. Used Disk Utility to burn it but when the verification process comes up, it verifies it, then gives me: Unable to verify disk image, burn failed. I'm using Memorex Single Layer DVD+RW; 4X; 4.7GB; 120min. CD/DVD Writer Is compatibile with all types. What do I do? I really need Leopard. Tiger is terrible and outdated. Do I need another Blank DVD, or something else. Haven't tried it on Toast yet. And when I had to erase the contents on the RW DVD it says capicity is zero KBs, or 102.4Mb. Need help. Thank You