mandrive 2006 and K3b

I installed mandriva 2006 (free download edition) today. Everything works as
it should, except the cd burning program.
I did not change any system parameters, it's just not working as installed
on my system.

My previous mandrake install (version 10.1) did not give any problems with
the same program.

When I try to burn, the program says:

i: "writing in TAO with speed 12x is started"
x: "mkisofs was not closed correctly"
x: "there's probably a buffer underrun"

and then the program stops - burning cannot even start.

Pushing the DEBUG button gives:

-----------------------------------------------------------------------------------------------------------
System
-----------------------
K3b Version: 0.12

KDE Version: 3.4.2
QT Version: 3.3.4
Kernel: 2.6.12-12mdk
Devices
-----------------------
LG CD-ROM CRD-8520B 1.00 (/dev/hdc, ) at /mnt/cdrom [CD-ROM] [Fout] [Geen ]

PLEXTOR CD-R PX-W1210A 1.00 (/dev/hdd, ) at /mnt/cdrom2 [CD-R; CD-RW;
CD-ROM] [Fout] [SAO; TAO; RAW; SAO/R96P; SAO/R96R; RAW/R16; RAW/R96P;
RAW/R96R]
K3b
-----------------------
Size of filesystem calculated: 84097

Used versions
-----------------------
mkisofs: 2.1.1a03
cdrecord: 2.1.1a03

cdrecord
-----------------------
/usr/bin/cdrecord: Cannot allocate memory. WARNING: Cannot do mlockall(2).
/usr/bin/cdrecord: WARNING: This causes a high risk for buffer underruns.
/usr/bin/cdrecord: Operation not permitted. WARNING: Cannot set RR-scheduler
/usr/bin/cdrecord: Permission denied. WARNING: Cannot set priority using
setpriority().
/usr/bin/cdrecord: WARNING: This causes a high risk for buffer underruns.
scsidev: '/dev/hdd'
devname: '/dev/hdd'
scsibus: -2 target: -2 lun: -2
Warning: Open by 'devname' is unintentional and not supported.
Linux sg driver version: 3.5.27
SCSI buffer size: 64512
Cdrecord-Clone 2.01.01a03-dvd (i686-pc-linux-gnu) Copyright (C) 1995-2005
Jörg Schilling
Note: This version is an unofficial (modified) version with DVD support
Note: and therefore may have bugs that are not present in the original.
Note: Please send bug reports or support requests to warly at mandriva.com.
Note: The author of cdrecord should not be bothered with problems in this
version.
TOC Type: 3 = CD-ROM XA mode 2
Using libscg version 'schily-0.8'.
Driveropts: 'burnfree'
atapi: 1
Device type : Removable CD-ROM
Version : 0
Response Format: 1
Vendor_info : 'PLEXTOR '
Identifikation : 'CD-R PX-W1210A'
Revision : '1.00'
Device seems to be: Generic mmc CD-RW.
/usr/bin/cdrecord: Operation not permitted. Cannot send SCSI cmd via ioctl

cdrecord command:
-----------------------
/usr/bin/cdrecord -v gracetime=2 dev=/dev/hdd speed=12 -tao
driveropts=burnfree -eject -overburn -multi -xa -tsize=84097s -

mkisofs
-----------------------
84097

mkisofs command:
-----------------------
/usr/bin/mkisofs -gui -graft-points -volid K3b data project -volset -appid
K3B THE CD KREATOR (C) 1998-2005 SEBASTIAN TRUEG AND THE K3B TEAM
-publisher
-----------------------------------------------------------------------------------------------

Is there anyone who has the same experience?
What should I do to solve the problem?

thanks in advance,

Oeps!?