Format of VINES request block for 25-th line messages:
Offset	Size	Description	)
 00h	DWORD	pointer to user-written message handler
 04h	DWORD	pointer to next request block (filled in by VINES)
 08h	DWORD	pointer to previous request block (filled in by VINES)
 0Ch	DWORD	pointer to message storage area (filled by VINES) (see #03443)