I think something went wrong with the config file (the app creates a .fluxweatherrc file in your home directory, maybe it made it wrong). I just updated the script so it falls back on default values if something goes wrong with the config file. You can download the file again here: http://yorik.uncreated.net/scripts/fluxweather.py
or simply delete the .fluxweatherrc file...
Tell me if it worked