result is not a function

result is not a function

Hello
I am trying:
$("#my_input").autocomplete("/settings/search_users", {
      width: 260,
      selectFirst: true,
      formatItem: formatItem,
      formatResult: formatResult
    });

    $(":text, textarea").result(log).next().click(function() {
      $(this).prev().search();
    });

but it doesn't work:
$(":text, textarea").result is not a function


What is wrong?