OK ... should be working.
You had element #19 set to hidden in the main element properties. This actually makes the element totally hidden, so it's "input type=hidden", and cannot then be shown via JS. And you only had one JS event, to hide #19 when 'other' is selected, you didn't have anything set up to hide it again if something other than 'other' is selected.
It's not entirely obvious, but to do what you want requires three JS events:
on change: show #19 if value == other
on change: hide #19 if value != other
on load: hide #19 if value != other
If you find that the 'change' event doesn't work in all browsers, you can use 'click' instead. For example, some earlier versions of IE don't correctly handle 'change' events.
If you have a look at how I've set up element #3, you should be able to do element #4 yourself. Just shotu if you have any issues with it.
-- hugh