Help needed debugging Jaycar theremin

I successfully put together the Jaycar theremin, tuned it quickly to get a rough pitch/volume response, and it worked for a day. However, the next day I brought it to a friend's house, and it stopped working. It would only produce a clicking sound when you touched the volume plate.

What do I do to find the problem? I have a multimeter, but no real idea how to systematically test the circuit and find the problem. Any advice, or links to good advice, would be greatly appreciated. My searches on 'finding short circuits' haven't got me very far yet. Any insight into common problems with the Jaycar kit would be great too. Please help!

Thanks,

Matt

There is nothing which you wouldn't find on ThereminWorld: http://thereminworld.com/forum.asp?cmd=p&T=4430&F=3