DL DVD - Verify pass but bad block and PI Failures

Burning Verbatim DVD+R DL bought from newegg. Burned 22 avi files using ImgBurn. Verification was successful and the sfv I included on the DVD passed (that took quite a long time to verify 22 350MB avi files!), but the Windows Event Log shows 12 cdrom errors and CDSpeed 4.7.7.5 quality is 0 (see attached).

I burned at 6x. XP SP2 with NEC 3550A. 2GB RAM burning from RAID0 array and no load on the PC, freshly booted even.

Any ideas?

Event Type: Error
Event Source: Cdrom
Event Category: None
Event ID: 7
Date: 10/9/2007
Time: 7:13:13 PM
Description:
The device, \Device\CdRom0, has a bad block.