Assuming that you want your display session encrypted. The link should be able to assist. Do a page search for "443".
Use something like, e.g., "x11vnc -rfbport 5901" to force it to use port 5901 (this is VNC display :1.) If something else is using that port x11vnc will exit immediately. If you do not supply the -rfbport option, it will autoprobe starting at 5900 and work its way up to 5999 looking for a free port to listen on. In that case, watch for the PORT=59xx line to see which port it found, then subtract 5900 from it for the VNC display number to enter into the VNC Viewer(s).
Following the above guidelines, did it work? If so, Congratulations!! you created an SSL encrypted connection between the SSL Java applet running in your web browser and x11vnc. The fact that you used HTTP instead of HTTPS to download the applet is not the end of the world (some users do it this way), the main thing is that the VNC traffic is encrypted with SSL. If you are having trouble even with the above baseline test case feel free to contact me (please send the Full x11vnc output, not just part of it; the complete x11vnc command line; the URL(s) entered in the browser; the full Java Console output; and anything else you can think of.)