Sounds like an earth problem, it usually is with anything electric :?
I've sent one of my axes to be rewired with my mate (who's promised not to use the flourscent pick wire that he has been). I have to change the pots and things over as the ones on there are CTS pots, but the type used in panel wiring so you can't get decent knobs to fit. This time he's using some connectors that slip on and off the pots so that I can change them. He's also made me a harness for the earth wires, one main wire and the rest ultrasonically welded to the main. Complete overkill, but I'm quite curious about how it will turn out.