What's wrong with my voltage multiplier segment?
It looks like you have things correctly connected, all though the top right cap isn't doing anything.  The output in your case is from the bottom right corner to the top left corner, J4 to J1 in the schematic.

At 50 Hz and 100 nF you're not going to get a lot of current capability, but it will be enough for a voltmeter to show you the high voltage.