autocomplete: not search if there are no corrispondce

autocomplete: not search if there are no corrispondce

hello,

i've using this plugin (with some my personalization)

http://blekm.altervista.org/autocomplete.custom.js
http://blekm.altervista.org/jquery.autocomplete.js
http://blekm.altervista.org/jquery.metadata.js

I've just a problem: all works fine, but if there are no result with one (ore more letter) the autocomplete start anyway and my php script return msg error (it's ok).

Is there a way to NOT use the php script if there are no corrispondce, and write something like "NO RESULT" into suggestion list? I hope I've explain right, if not tell me I'll explain again