Twain-app does not work anymore Win98->XP

[Sektionschef]

Dear all
Many years ago I wrote a sw in plain VB code(no external control) which has implemented communication to a scanner via Twain Interface.
At this time the used OS was Windows 98. The application was running fine since present.
Now, I have moved this app onto a WindowsXP system and the app is not working anymore.
Strange thigs are happening like:
I negotiate a certain capability, sometimes the scanner accepts it, sometimes the negotiation fails. Once it fails then any further negoition fails until I restart the app. In addition every negotiation fails when running the compiled exe while most negotiations work while running the sw in the IDE. Opening the DSM and DS always works without any problems.
I haven’t worked out yet what capabilies exactly fail to negotiate(I think one is XFERMECH) but does anyone know why there is such a difference between Win98 and XP?
Do I need to modify the way how I use the Win32 API in my program?
Regards
Sektionschef

[Sektionschef]

Hi
I made some further investigations and found out that I got a TW_Failure result code when I set a certain capability. However, the scanner SETS the capability correctly but returns TW_Failure. This happens only in WinXP while I always get a TW_Success in Win98.
Querying the capabilities does not show the problem, I always get a TW_Success regardless what OS I am using.
Any ideas what maight be wrong here?
Regards
Sektionschef

[Author]

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