What port did you change the web port to?
8000 is the 'media port' used by the Hikvision 'command and control' dialogues, it's nothing to do with the HTTP web admin port. Standard SADP doesn't show or allow you to change the HTTP web admin port.
If you are not sure what the port is currently set to, you can query the camera with the very good Windows tool 'ONVIF Device Manager' from sourceforge.net
You should be able to confirm what the ports are set to in the 'Network settings' page.