WifiGeckoReader allows you to view the gecko debug messages over the wifi connection. Only use this when debugging. There is no need to use it regularly. Set wifi_gecko=no when not needed.
It uses UDP port 4405.
To make it work with wiiflow, edit or add the following wiiflow.ini lines:
[DEBUG]
wifi_gecko=yes
wifi_gecko_port=4405
wifi_gecko_ip=your.computer.ipAddr.here
eg:
wifi_gecko_ip=192.168.0.199
Once this is done, run WifiGeckoReader, then run wiiflow. You should start seeing debug messages.