Question: how to install xymon client?
Answer: SSH in as root. Drop into the CLI.
vi /usr/local/www/xymon/client/etc/xymonclient.cfg. point to your xymon-server and port.
/usr/local/etc/rc.d/xymon-client onestop.
/usr/local/etc/rc.d/xymon-client onestart.