>In lnretval=PrintWindow(...
>
> Using GetDesktopWindow()
> I got the same error
>
> Using the value of GetDesktopWindow()
> I see the print dialog box with the default printer
> ok. Bravo
>
> BUT If I click on the Ok button
> no printing and lnretval=0

Hmmm...try this, using the explicit DLL, see if it helps any:

declare integer GetDesktopWindow in user32.dll

That part works, correct? Then, also try

nWhand = GetDesktopWindow()
? nWhand

These shouldn't matter, but let's try anyway...