Failure to read a Bluray disk with 'dvdbackup' command

[Yuri]

My attempts to backup a Bluray disk with this command fail:

# dvdbackup -M
libdvdread:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.IFO failed
libdvdread:DVDOpenFileUDF:UDFFindFile /VIDEO_TS/VIDEO_TS.BUP failed
libdvdread: Can't open file VIDEO_TS.BUP.
Cannot open Video Manager (VMG) info.
Mirror of DVD failed

System log gets this message repeated many times logged  during 
dvdbackup command:
Apr  4 12:32:48 yuri kernel: (cd0:ata2:0:1:0): READ DVD STRUCTURE. CDB: 
ad 00 00 00 00 00 00 01 00 08 00 00
Apr  4 12:32:48 yuri kernel: (cd0:ata2:0:1:0): CAM status: SCSI Status Error
Apr  4 12:32:48 yuri kernel: (cd0:ata2:0:1:0): SCSI status: Check Condition
Apr  4 12:32:48 yuri kernel: (cd0:ata2:0:1:0): SCSI sense: ILLEGAL 
REQUEST asc:30,2 (Cannot read medium - incompatible format)
Apr  4 12:32:48 yuri kernel: (cd0:ata2:0:1:0): Retrying command (per 
sense data)

The device is recognized as:
Apr  4 12:06:50 yuri kernel: cd0 at ata2 bus 0 scbus0 target 1 lun 0
Apr  4 12:06:50 yuri kernel: cd0: <HL-DT-ST BD-RE  WH16NS40 1.00> 
Removable CD-ROM SCSI device
Apr  4 12:06:50 yuri kernel: cd0: Serial Number K9LDC482430
Apr  4 12:06:50 yuri kernel: cd0: 33.300MB/s transfers (UDMA2, ATAPI 
12bytes, PIO 8192bytes)
Apr  4 12:06:50 yuri kernel: cd0: 22687MB (11616096 2048 byte sectors)

Anybody can tell what might be wrong?

10.3-PRERELEASE
dvdbackup-0.4.2_3
libdvdcss-1.3.99

Thank you,
Yuri