VNC server for Amiga is hellish task, as there is no dedicated video memory in the system.
Polling the active screen is tricky, as the screen may be pushed back any time. As for AGA screens it can be even pulled down half the way, making visible upper half of the screen from behind (Yea, The wizard Copper can change the current display memory any time).
avnc was designed to use special feature of picasso96 and because of that simply does not work with CybergraphX. But the client avv (AmiVncViewer) from that page works really nice.
Cheers
