SONY DVD RW DRU-720A burn failure with Sony dual layer disks

Hi Everyone,

Today I suffered 2 - DVD+R DL burn failures , on my WinXP Pro SP3 computer. I was attempted to burn with both DVDFabPlatinum 5.1.1.0 and Nero 7 burning ROM. I was trying to write DVD files.
I tried with 2-separate DVD titles , that I had on my hard drive. Both DVD movies play back fine on my computer. I just can't get either one on a disk.
I'm using my SONY DVD RW DRU-720A external USB 2.0 burner. The drive works fine with 4.7 GB. DVDs . For the DVD 8.5 GB disks, I'm using Sony DVD+R DL disks .
The burn failure I had with DVDFab Platinum 5.1.1.0 , had a sudden "device unaccessible" error while the burn was working.
And I used DVDFab Platinum 5.1.1.0 to reset my DMA, but that didn't help.
With Nero 7 burning ROM , I first had a successful burn with a DVD 4.7 disk, but when I tried burning a 6.45 GB DVD folder , to a Sony DVD+R DL disk , it failed. I selected my recorder to the "physical disk type" for book type , and to "write extended lead out to dual layer disks" in Nero recorder settings. All started out well, but then I got some sort of "address error" and Nero said burn failure .
I'm attaching my Nero log with this post.
I've had my SONY DVD RW DRU-720A drive for about 1-1/2 years, and this is only the 2nd time I've burned to DVD+R DL disks.

The previous time worked , but I used Verbatim disks, not Sony disks. I thought Sony disks would work well with a Sony burner ?
Could someone look over my Nero log file, and give me some feedback on what the problem may be ? This very frustrating , and these dual layer disks are expensive !
Thanks .

Your Sony branded discs are actually made by RiTEK, with media code RITEK D01 (as found in your error log).

It's pretty much hit or miss with any DL discs apart from Verbatim, I'm afraid.

Try some more Verbatim discs would be my advice.

Today I tried burning with Verbatim DW+RW DL disc's . The first burn worked . The 2nd and 3rd were failures . I'm attaching the Nero burn logs for the two failures??????????
I cleaned the lens on my SONY DVD RW DRU-720A before the failures .
The video files I'm attempting to burn are on my External USB connected hard drive . Could that cause any problems ?

Yeah, I wouldn't burn from USB device to USB device personally.

I'd stick to using an internal HDD as the source if you can.