DVD+RL Problem

[Ken Mandelberg <km@mathcs.emory.edu>]

I'm trying to use growisofs to write a DVD+RL disk on Solaris 10/Sparc 
using a Plextor PX-740A. At first I was hopeful, there seemed to be no 
error in the write

I issued

 growisofs -dvd-compat  -Z /dev/rdsk/c1t2d0s0=/big/contact.iso

and the last few lines of output after 40 minutes are


7887519744/7909691392 (99.7%) @2.4x, remaining 0:06
7898726400/7909691392 (99.9%) @2.4x, remaining 0:03
builtin_dd: 3862160*2KB out @ average 2.4x1385KBps
/dev/rdsk/c1t2d0s0: flushing cache
/dev/rdsk/c1t2d0s0: closing track
/dev/rdsk/c1t2d0s0: closing disc

However, nothing I tried can read the disk, and mediainfo thinks it blank

orac(3,29): dvd+rw-mediainfo /dev/rdsk/c1t2d0s0
INQUIRY:                [PLEXTOR ][DVDR   PX-740A  ][1.01]
GET [CURRENT] CONFIGURATION:
 Mounted Media:         2Bh, DVD+R Double Layer
 Current Write Speed:   2.4x1385=3324KB/s
 Write Speed #0:        2.4x1385=3324KB/s
GET [CURRENT] PERFORMANCE:
 Write Performance:     2.4x1385=3324KB/s@[0 -> 4173823]
 Speed Descriptor#0:    00/4173823 R@4.7x1385=6527KB/s W@2.4x1385=3324KB/s
DVD+R DOUBLE LAYER BOUNDARY INFORMATION:
 L0 Data Zone Capacity: 2086912*2KB, can still 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:           4173824*2KB
 Track Size:            4173824*2KB
 ROM Compatibility LBA: 265696
READ CAPACITY:          1*2048=2048


Any ideas?