Scraping a Webpage for Results Using PHP cURL - Post Not Working

I'm new to using cURL, but from what I have read, the following should post the variables to the page, then print the result. The result prints, but it doesn't seem like the POST variables went because no results are generated. FireBug doesn't show anything going either. Any ideas what I'm doing wrong?

Thanks for your help!

 // create curl resource
        $ch = curl_init();

        // set url
        curl_setopt($ch, CURLOPT_URL, "http://butlercountyclerk.org/bcc-11112005/ForeclosureSearch.aspx");


        $data = array(
            'Search:btnSearch' => 'Search',
            'Search:ddlMonth' => '1',
            'Search:ddlYear' => '2011'
        );


        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data); 

        //return the transfer as a string
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);

        // $output contains the output string
        $output = curl_exec($ch);

        // close curl resource to free up system resources
        curl_close($ch);

        echo $output;