> but my program is rather very simple
>
> begin
> loadDll
> ...
> unloaddll
> end
>
> so i unload the DLL only at the end !

Why do you think that this is the end? Not at all. After that code in
finalization sections is executed.
Try to comment unloaddll out. Actually, I don't see any point to
unload it explicitly because Windows will unload all libraries
automatically at application end.

SY, SD.