I've installed the fluxgui package from Killian Valkhof's PPA (https://launchpad.net/~kilian/+archive/f.lux) and started the applet by pressing alt+f2 and typing in fluxgui.
The inidcator icon shows up and I've entered my latitude/longitude, but my screen colors aren't changing. The applet fails to open its preferences dialogue as well.
What gives? Any solutions?