can not find element using watir webdriver

I am trying to click on the button.

<input data-ember-action="797" value="Search Now" class="cta-1st clrboth primary search-button firepath-matching-node" type="button">

but it keep showing an error of not finding the element to click. it finds all the elements until the end but when it comes to "click" it throws an error. My code is like this:

 @browser.div(:id=>'ember730').section(:class=>'tab-pane fade active in').form(:class=>'flight-search ').input(:class=>'cta-1st clrboth primary search-button').click

Am I missing something? I am using Watir