Burning error

Most of the time when I try to backup a DVD it works fine. But a few times Ive gotten an error that I dont understand. I have searched the forum for a solution but didnt have any luck, even though this has probably been addressed countless times already.

The following is the error message that I am getting. Can someone help me with how to fix this?

Windows XP 5.1
IA32
WinAspi: -
ahead WinASPI: File ‘C:\Program Files\Ahead\Nero\Wnaspi32.dll’: Ver=2.0.1.68, size=160016 bytes, created 7/28/2004 4:51:12 PM
Nero API version: 6.6.0.1
Using interface version: 6.3.1.4
Installed in: C:\Program Files\Ahead\Nero
Application: ahead\Nero - Burning Rom
Recorder: <MATSHITA DVD-RAM UJ-841S>Version: 1.60 - HA 1 TA 0 - 6.6.0.1
Adapter driver: <atapi> HA 1
Drive buffer : 2048kB
Bus Type : via Inquiry data (1) -> ATAPI, detected: ATAPI
Connected to MMC as unknown drive with class-nr : 1
Drive is autodetected - recorder class: Std. MMC recorder

=== Scsi-Device-Map ===
DiskPeripheral : TOSHIBA MK1234GSX atapi Port 0 ID 0 DMA: On
CdRomPeripheral : MATSHITA DVD-RAM UJ-841S atapi Port 1 ID 0 DMA: On

=== CDRom-Device-Map ===
MATSHITA DVD-RAM UJ-841S D: CDRom0

AutoRun : 1
Excluded drive IDs:
WriteBufferSize: 83886080 (0) Byte
ShowDrvBufStat : 0
BUFE : 0
Physical memory : 1013MB (1038316kB)
Free physical memory: 522MB (534864kB)
Memory in use : 48 %
Uncached PFiles: 0x0
Use Static Write Speed Table: 0
Use Inquiry : 1
Global Bus Type: default (0)
Check supported media : Disabled (0)

17.8.2006
NeroAPI
8:53:49 PM #1 Phase 112 File APIProgress.cpp, Line 276
DVD-Video files reallocation started

8:53:49 PM #2 DVDREALLOC -21 File DVDVideoCompilation.cpp, Line 1183
Required file ‘VIDEO_TS.VOB’ is not present

8:53:49 PM #3 Phase 115 File APIProgress.cpp, Line 276
DVD-Video files reallocation failed

8:53:49 PM #4 Text 0 File NeroAPIBurnFS.cpp, Line 206
Failed to realloc DVD video files

Existing drivers:
File ‘Drivers\PXHELP20.SYS’: Ver=2.03.32a, size=20640 bytes, created 4/25/2005 5:03:00 AM (Prassi/Veritas driver for win 2K)

Registry Keys:
HKLM\Software\Microsoft\Windows NT\CurrentVersion\WinLogon\AllocateCDROMs : 0 (Security Option)

update nero to 6.6.0.18