DVD+R DL writing failed

[Dorin Lazar <lazar@deuromedia.ro>]

  Hello,
  I have a NEC ND-3500AG which is supposed to support writing DL DVDs. I am 
trying to use the dvd+rw-tools as packaged in Fedora Core 3, that is:
  dvd+rw-tools-5.21.4.10.8 with an 'open-exclusive' patch. It burns DVD+-R(W) 
without a problem.
  When it comes to DVD+R DL I encounter the following problem:
Executing 'mkisofs -udf /home/mmb/media/dvd_image | builtin_dd of=/dev/dvd 
obs=32k seek=0'
:-? L0 Data Zone Capacity is set already
/dev/dvd: "Current Write Speed" is 1.0x1385KBps.
:-[ WRITE@LBA=0h failed with SK=5h/ASC=30h/ACQ=05h]: Wrong medium type
:-( media is not formatted or unsupported.
:-( write failed: Wrong medium type

  The message about L0 is probably due to the several retries on the same 
media, however the most curious message is ":-[ WRITE@LBA=0h failed with 
SK=5h/ASC=30h/ACQ=05h]: Wrong medium type". I looked in the keys.txt file for 
the code 05 30 05, but it wasn't there. The closest match is:
"2  30  05       CANNOT WRITE MEDIUM - INCOMPATIBLE FORMAT".
  However, this shouldn't be the case. The front panel of the writer 
advertises that is supports DVD+R DLs.
  I paste here the output of the dvd+rw-mediainfo /dev/dvd

INQUIRY:                [_NEC    ][DVD_RW ND-3500AG][2.16]
GET [CURRENT] CONFIGURATION:
 Mounted Media:         2Bh, DVD+R Double Layer
 Media ID:              RITEK/D01
 Current Write Speed:   6.1x1385=8467KB/s
 Write Speed #0:        6.1x1385=8467KB/s
 Write Speed #1:        5.1x1385=7056KB/s
 Write Speed #2:        4.1x1385=5645KB/s
 Write Speed #3:        3.1x1385=4234KB/s
 Write Speed #4:        2.0x1385=2822KB/s
 Write Speed #5:        1.0x1385=1411KB/s
GET [CURRENT] PERFORMANCE:
 Write Performance:     1.0x1385=1385KB/s@[0 -> 3994816]
:-( empty GET PERFORMACE descriptor
DVD+R DOUBLE LAYER BOUNDARY INFORMATION:
 L0 Data Zone Capacity: 1997408*2KB, can no longer be set
READ DISC INFORMATION:
 Disc status:           blank
 Number of Sessions:    1
 State of Last Session: empty
 Number of Tracks:      1
READ TRACK INFORMATION[#1]:
 Track State:           blank
 Track Start Address:   0*2KB
 Next Writable Address: 0*2KB
 Free Blocks:           3994816*2KB
 Track Size:            3994816*2KB
 ROM Compatibility LBA: 262144
READ CAPACITY:          1*2048=2048

  The drive is an IDE drive. The kernel is 2.6.11.11. No suspect messages were 
to be found the kernel logs.
  What does the error actually mean? Is there anything I can do? Is it 
possible to write DLs on that drive? Is it an unsupported drive type?
  Thank you,
    Dorin