I've installed the ubuntu version into my kubuntu. After launching it does nothing. Which isn't strange because the /usr/bin/xflux is a 32-bit binary and the package didn't request the required libraries. I have to consider it doesn't support 64-bit linux. Come on. Linux is not Windows. Everybody and their dog already run 64-bit version. It makes no sense not to. All the software is built for 64-bit too. It's just a…
I have it running fine under 64-bit Ubuntu, sounds like it might be a problem with KDE. Have you tried looking around for other packages for it?
This doesn't sound like a KDE problem:
% ldd `which xflux`
linux-gate.so.1 => (0xf773b000)
libXxf86vm.so.1 => not found
libXext.so.6 => not found
libX11.so.6 => not found
libstdc++.so.6 => not found
libm.so.6 => /lib32/libm.so.6 (0xf76f6000)
libgcc_s.so.1 => not found
libc.so.6 => /lib32/libc.so.6 (0xf754e000)
/lib/ld-linux.so.2 (0xf773c000)