write errors K3B: cdrecord cannot allocate memory

I get this message in the debug window while running K3B 0.12.17 using KDE 3.5.4-16.el5.centos on CentOS5.2.
Doesn't matter which iso i want to burn.
A full output from the debugger is below. Any comments what could be wrong?

System
-----------------------
K3b Version: 0.12.17

KDE Version: 3.5.4-16.el5.centos CentOS
QT Version:  3.3.6
Kernel:      2.6.18-92.1.6.el5PAE
Devices
-----------------------
_NEC DVD_RW ND-3520A 1.04 (/dev/scd0, ) at  [CD-R; CD-RW; CD-ROM; DVD-ROM; DVD-R; DVD-RW; DVD+R; DVD+RW; DVD+R DL] [DVD-ROM; DVD-R Sequential; DVD-RW Restricted Overwrite; DVD-RW Sequential; DVD+RW; DVD+R; DVD+R Double Layer; CD-ROM; CD-R; CD-RW] [SAO; TAO; RAW; SAO/R96R; RAW/R96R; Restricted Overwrite]

Used versions
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cdrecord: 2.1

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/scd0'
devname: '/dev/scd0'
scsibus: -2 target: -2 lun: -2
Linux sg driver version: 3.5.27
/usr/bin/cdrecord: Warning: using inofficial libscg transport code version (schily - Red Hat-scsi-linux-sg.c-1.83-RH '@(#)scsi-linux-sg.c 1.83 04/05/20 Copyright 1997 J. Schilling').
SCSI buffer size: 64512
Cdrecord-Clone 2.01 (cpu-pc-linux-gnu) Copyright (C) 1995-2004 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 http://bugzilla.redhat.com/bugzilla
Note: The author of cdrecord should not be bothered with problems in this version.
TOC Type: 1 = CD-ROM
Using libscg version 'schily-0.8'.
Driveropts: 'burnfree'
atapi: 1
Device type    : Removable CD-ROM
Version        : 5
Response Format: 2
Capabilities   :
Vendor_info    : '_NEC    '
Identifikation : 'DVD_RW ND-3520A '
Revision       : '1.04'
Device seems to be: Generic mmc2 DVD-R/DVD-RW.
Current: 0x0009
Profile: 0x002B
Profile: 0x001B
Profile: 0x001A
Profile: 0x0014
Profile: 0x0013
Profile: 0x0011
Profile: 0x0010
Profile: 0x000A
Profile: 0x0009 (current)
Profile: 0x0008 (current)
Using generic SCSI-3/mmc   CD-R/CD-RW driver (mmc_cdr).
Driver flags   : MMC-3 SWABAUDIO BURNFREE
Supported modes: TAO PACKET SAO SAO/R96R RAW/R96R
Drive buf size : 1343488 = 1312 KB
FIFO size      : 4194304 = 4096 KB
/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.
Track 01: data    15 MB        
Total size:       17 MB (01:44.89) = 7867 sectors
Lout start:       17 MB (01:46/67) = 7867 sectors
Current Secsize: 2048
ATIP info from disk:
  Indicated writing power: 5
  Is not unrestricted
  Is not erasable
  Disk sub type: Medium Type B, low Beta category (B-) (4)
  ATIP start of lead in:  -11607 (97:27/18)
  ATIP start of lead out: 359849 (79:59/74)
Disk type:    Short strategy type (Phthalocyanine or similar)
Manuf. index: 18
Manufacturer: Plasmon Data systems Ltd.
Blocks total: 359849 Blocks current: 359849 Blocks remaining: 351982
Starting to write CD/DVD at speed 32 in dummy SAO mode for single session.
Last chance to quit, starting dummy write in 2 seconds.
   1 seconds.
   0 seconds. Operation starts.
Waiting for reader process to fill input buffer ... input buffer ready.
trackno=0
BURN-Free is OFF.
Turning BURN-Free on
Sending CUE sheet...
/usr/bin/cdrecord: WARNING: Drive returns wrong startsec (0) using -150
Writing pregap for track 1 at -150
Starting new track at sector: 0
Track 01:    0 of   15 MB written.
/usr/bin/cdrecord: Input/output error. write_g1: scsi sendcmd: no error
CDB:  2A 00 00 00 00 BA 00 00 1F 00
status: 0x2 (CHECK CONDITION)
Sense Bytes: 70 00 04 00 00 00 00 0A 00 00 00 00 08 03 00 00
Sense Key: 0x4 Hardware Error, Segment 0
Sense Code: 0x08 Qual 0x03 (logical unit communication crc error (ultra-dma/32)) Fru 0x0
Sense flags: Blk 0 (not valid)
cmd finished after 0.003s timeout 200s
/usr/bin/cdrecord: A write error occured.
/usr/bin/cdrecord: Please properly read the error message above.
write track data: error after 380928 bytes
Writing  time:    5.291s
Average write speed  20.6x.
Fixating...
/usr/bin/cdrecord: Input/output error. flush cache: scsi sendcmd: no error
CDB:  35 00 00 00 00 00 00 00 00 00
status: 0x2 (CHECK CONDITION)
Sense Bytes: 70 00 03 00 00 00 BB 0A 00 00 00 00 0C 07 00 00
Sense Key: 0x3 Medium Error, Segment 0
Sense Code: 0x0C Qual 0x07 (write error - recovery needed) Fru 0x0
Sense flags: Blk 187 (not valid)
cmd finished after 12.975s timeout 200s
WARNING: Some drives don't like fixation in dummy mode.
Trouble flushing the cache
Fixating time:   12.983s
/usr/bin/cdrecord: fifo had 70 puts and 7 gets.
/usr/bin/cdrecord: fifo was 0 times empty and 1 times full, min fill was 90%.
BURN-Free was never needed.

cdrecord command:
-----------------------
/usr/bin/cdrecord -v gracetime=2 dev=/dev/scd0 speed=32 -dao -dummy driveropts=burnfree -eject -data /home/ralf/Download/kiss/KiSS_DP-601_4[1].0.6b_fw.iso