dvd multi-session

[rich turner <rich@storix.com>]

i have seen this question asked a couple of times and as far as i can 
tell multi-session should be possible on dvd. i have tried using both 
cdrecord-prodvd and dvd+rw tools to write multi-session disks and both 
are failing. i have a pioneer dvr105 using media supplied with drive. is 
it prodvd, the media, the drive, or a limitation with dvd's not being 
able to be written in multi-session? is there any utility that will 
allow for multi-session writes for my drive?
below are my results for prodvd

# cdrecord-prodvd --version
Cdrecord-ProDVD-Clone 2.0.1 (i586-pc-linux-gnu) Copyright (C) 1995-2002 
J?rg Schilling
Unlocked features:
Limited  features:

# cdrecord-prodvd dev=0,0,0 -v -multi home_stx.tar
works great!

# cdrecord-prodvd dev=0,0,0 -toc
first: 1 last 1
track:   1 lba:         0 (        0) 00:02:00 adr: 1 control: 4 mode: -1
track:lout lba:      7840 (    31360) 01:46:40 adr: 1 control: 4 mode: -1

# cdrecord-prodvd dev=0,0,0 -multi etc_stx.tar

Cdrecord-ProDVD-Clone 2.0.1 (i586-pc-linux-gnu) Copyright (C) 1995-2002 
J?rg Schilling
Unlocked features:
Limited  features:
scsidev: '0,0,0'
scsibus: 0 target: 0 lun: 0
Linux sg driver version: 3.1.24
Using libscg version 'schily-0.7'
Device type    : Removable CD-ROM
Version        : 0
Response Format: 2
Capabilities   :
Vendor_info    : 'PIONEER '
Identifikation : 'DVD-RW  DVR-105 '
Revision       : '1.21'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
cdrecord-prodvd: This version of cdrecord limits DVD-R/DVD-RW support to 
-dummy or 1 GB real.
cdrecord-prodvd: If you need full DVD-R/DVD-RW support, ask the Author 
for cdrecord-ProDVD.
Using generic SCSI-3/mmc-2 DVD-R/DVD-RW driver (mmc_dvd).
Driver flags   : DVD SWABAUDIO BURNFREE
Supported modes: TAO PACKET SAO SAO/R96P SAO/R96R RAW/R16 RAW/R96P RAW/R96R
cdrecord-prodvd: Drive needs to reload the media to return to proper status.
WARNING: Phys disk size 7840 differs from rzone size 0! Prerecorded disk?
WARNING: Phys start: 196608 Phys end 204447
Starting to write CD/DVD at speed 2 in real TAO mode for multi session.
Last chance to quit, starting real write    0 seconds. Operation starts.
cdrecord-prodvd: Input/output error. reserve_rzone: scsi sendcmd: no error
CDB:  53 00 00 00 00 00 00 10 8B 00
status: 0x2 (CHECK CONDITION)
Sense Bytes: 70 00 05 00 00 00 00 0E 00 00 00 00 30 05 00 00
Sense Key: 0x5 Illegal Request, Segment 0
Sense Code: 0x30 Qual 0x05 (cannot write medium - incompatible format) 
Fru 0x0
Sense flags: Blk 0 (not valid)
cmd finished after 0.005s timeout 100s