k3b fails to blank rw cd wodim can't open scsi

Binary package hint: k3b

On updated/upgraded Jaunty [my pc internal reference pc_tavolo ]

Description: Ubuntu jaunty (development branch)
Release: 9.04

erasing RW cd k3b fails... all works fine with Brasero

apt-cache policy k3b
k3b:
  Installato: 1.0.5-3ubuntu1
  Candidato: 1.0.5-3ubuntu1
  Tabella versione:
 *** 1.0.5-3ubuntu1 0
        500 http://archive.ubuntu.com jaunty/main Packages
        100 /var/lib/dpkg/statu

the permissions of /dev/sr0

ls -la /dev/sr0
brw-rw----+ 1 root cdrom 11, 0 2009-02-15 10:21 /dev/sr0

Here the error coming from k3b

devname: '/dev/sr0'
scsibus: -2 target: -2 lun: -2
Error trying to open /dev/sr0 exclusively (Device or resource busy)... retrying in 1 second.
Error trying to open /dev/sr0 exclusively (Device or resource busy)... retrying in 1 second.
Error trying to open /dev/sr0 exclusively (Device or resource busy)... retrying in 1 second.
Error trying to open /dev/sr0 exclusively (Device or resource busy)... retrying in 1 second.
Error trying to open /dev/sr0 exclusively (Device or resource busy)... giving up.
/usr/bin/wodim: Device or resource busy.
Cannot open SCSI driver!
For possible targets try 'wodim --devices' or 'wodim -scanbus'.
For possible transport specifiers try 'wodim dev=help'.
For IDE/ATAPI devices configuration, see the file README.ATAPI.setup from
the wodim documentation.
TOC Type: 1 = CD-ROM

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Just while i'm reporting this bug with same disk and without touching nothing else.
I close k3b
I opened Brasero and the erase/burn process was completed fine without any errors.

Thank you