Where did you get this example from? This example seems much cleaner..
I think the bottom two lines aren't meant to be there.
Code:
{{ dhtml.inputbox{value: __request.args.q, button: "Search 'Tree'", field: "q", publish: page.uri} }}
{{ if(__request.args.q) { wiki.search(__request.args.q, nil, nil, "path:Tree/*"); } }}
This example will search subpages of the "Tree" page for the text you enter into the box. I don't know if you have a page called Zzhelp, but if you don't, you won't get interesting results!