Why I use the multisession burn DVD ,there are some strange thing happen?

vbimport

#1

I use the Nero 6.319;and use this version NeroSDKAPI (in C++);
I use the NeroImportDataTrack() funcation to import the session in the DVD+RW;follow I add this files that come from the DVD to my Item Tree,
then burn to the DVD+RW;
after Burn ; take the DVD+RW out of the Device ;and Insert to the DVD again;
I can see my all the Item ( The Old Item and the new Item) on the DVD;
but ,strange thing is that ,the Old Item ,can not be opened ;and the new Item
can opened;I use the textediter to open the Old Item; the content is strange ;
these are diffrent before I burn this DVD;veracious ,the filesize is right,but the
code is not right;
I think about wether the filesystem is not right;
here is my key code,can some body can tell me ;what wrong;

the import session code;
<code>
NERO_IMPORT_DATA_TRACK_INFO nidti;
NERO_IMPORT_DATA_TRACK_RESULT nidtr;

		dwFlags = NIITEF_IMPORT_ISO_ONLY;
		
		memset (&nidti, 0, sizeof (nidti));
		nidti.nidtiSize = sizeof (nidti);
		

		pItem = NeroImportDataTrack (m_ndhDeviceHandle,
			iSessionToImport,
			&m_pCDStamp,
			&nidti,
			dwFlags,
			&nidtr,
			NULL);

</code>

this is use the ImportSession add to the new Items tree;
<code>
NERO_CITE_ARGS citeArgs;
dwFlags = 0;
memset (&citeArgs, 0, sizeof (citeArgs));

dwFlags |= NCITEF_CREATE_ISO_FS;

citeArgs.dwBurnOptions = dwFlags;
citeArgs.name = m_strCDName;
citeArgs.firstRootItem = pItem;


*ppIsoTrack = NeroCreateIsoTrackEx (NULL,
	(const char *) &citeArgs,
	NCITEF_USE_STRUCT);

</code>

this is burn funcation;

<code>
m_BurnFlag =
NBF_WRITE
| NBF_DISABLE_ABORT
| NBF_DETECT_NON_EMPTY_CDRW
| NBF_SPEED_IN_KBS
| NBF_CLOSE_SESSION
| NBF_CD_TEXT
| NBF_BUF_UNDERRUN_PROT;

iRes = NeroBurn (m_ndhDeviceHandle ,
NERO_ISO_AUDIO_MEDIA
,&writeCD,
m_BurnFlag,
0,
&m_npProgress);
</code>

hopy anybody can tell ,I am crarze;