npUserData in NERO_PROGRESS

I am using nero api version 6.
What is this npUserData in the NERO_PROGRESS, as I read the Documents and understand it’s just a pointer to object or something that we can use in the call back functions.

In my program when I set this pointer to a DUMMY_USER_DATA as it’s used in the console sample, my program work fine. but, in the case of creating a vcd, when the file is an AVI it will exit with Unexpected exception.

1A23-0085-7030-1431-5809-7099

Windows XP 5.1
IA32
WinAspi: -
ahead WinASPI: File ‘D:\Program Files\Ahead\Nero\Wnaspi32.dll’: Ver=2.0.1.59, size=160016 bytes, created 2003/12/16 07:18:06 È.Ù
Nero API version: 6.3.0.2
Using interface version: 6.0.0.0
Installed in: D:\Program Files\Ahead\Nero
Application: ahead\Nero - Burning Rom
Recorder: <Slimtype COMBO LSC-24081>Version: 3ME1 - HA 1 TA 1 - 6.3.0.2
Adapter driver: <atapi> HA 1
Drive buffer : 2048kB
Bus Type : default (0) -> ATAPI, detected: ATAPI

=== Scsi-Device-Map ===
DiskPeripheral : WDC WD600BB-00CAA1 atapi Port 0 ID 0 DMA: On
CdRomPeripheral : _NEC CD-ROM CD-3002A atapi Port 0 ID 1 DMA: Off
CdRomPeripheral : Slimtype COMBO LSC-24081 atapi Port 1 ID 1 DMA: On

=== CDRom-Device-Map ===
_NEC CD-ROM CD-3002A G: CDRom0
Slimtype COMBO LSC-24081 H: CDRom1

AutoRun : 1
Excluded drive IDs:
CmdQueuing : 1
CmdNotification: 2
WriteBufferSize: 83886080 (0) Byte
ShowDrvBufStat : 0
EraseSpeed : 0
BUFE : 0
Physical memory : 767MB (785904kB)
Free physical memory: 361MB (370144kB)
Memory in use : 52 %
Uncached PFiles: 0x0
Use Static Write Speed Table: 0
Use Inquiry : 1
Global Bus Type: default (0)
Check supported media : Disabled (0)

6.3.2004
NeroAPI
03:19:13 È.Ù #1 Phase 82 File APIProgress.cpp, Line 253
Encoding video

03:19:13 È.Ù #2 Text 0 File VCDCompilationImpl.cpp, Line 489
Using Nero Video Converter version 0.00

03:19:14 È.Ù #3 Text 0 File AVIVCDFileItem.cpp, Line 873
Encoding D:\1.avi to \NERF5.tmp
ScalingType: 0 Video: yes Audio: yes
File size: 198772736 bytes
Resolution: 352x240 25 Hz
Frames: 60325

03:19:14 È.Ù #4 Text 0 File AVIVCDFileItem.cpp, Line 886
Playing time: 2413.000000 s
Requested rate: 225 KB/s
iVideoRate=0
iAudioRate=32
Estimated size: 180975 blocks

03:19:14 È.Ù #5 Text 0 File Burncd.cpp, Line 5570
Unexpected exception

Existing drivers:

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