I use lots of LEDs and CFLs with different X10 modules. Also use many LED XMAS strings. All for one to two years now. I too ran into similar problems. So my solution was to leave atlest one incandence bulb in the circuit. I suppose that is like putting a resistor across the load.
I use SW13A, LM15A, lamp modules and 3pin appliance modules and all work fine with LEDs and CFLs and these are old modules bought few years back.