PHP Google Scraping Function

gistfile1.aw

function findranking($domain, $keyword) {

    usleep(400000*rand(0,16)); //set random interval between checks
    $url="http://www.google.com/search?q=".urlencode($keyword)."&num=100";
    $ch = curl_init($url);

    curl_setopt($ch, CURLOPT_HEADER,1); // set to 0 to eliminate header info from response
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1); // Returns response data instead of TRUE(1)
    $header = array();
    $header[0] = "Accept: text/xml,application/xml,application/xhtml+xml,";
    $header[0] .= "text/html;q=0.9,text/plain;q=0.8,image/png,*/*;q=0.5";
    $header[] = "Cache-Control: max-age=0";
    $header[] = "Connection: keep-alive";
    $header[] = "Keep-Alive: 300";
    $header[] = "Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7";
    $header[] = "Accept-Language: en-us,en;q=0.5";
    $header[] = "Pragma: "; // browsers keep this blank.
    curl_setopt( $ch, CURLOPT_HTTPHEADER, $header  );
    curl_setopt( $ch, CURLOPT_USERAGENT, $useragents[rand(0, sizeof($useragents)-1)] );
    $resp = curl_exec($ch); //execute post and get results

    curl_close ($ch);
    if(strpos($resp, "Location: http://sorry.google.com/sorry/") && strpos($resp, "302 Found")) 
       return -200;
    $count=0;
    $bp=0;

    while($bp=strpos($resp, "<h3 class=", $bp+1)) {
        $count++;
        $end=strpos($resp, "</h3>", $bp);
        $link= substr($resp, $bp, $end-$bp+5);
        $bp++;
        if(stripos($link, ">Local business results for") && stripos($link, "href=\"http://maps.google.com/")){
            $count--;
            }
        // match all secure and www non-www
        if(stripos($link, "http://".$domain) || stripos($link, "https://".$domain) || stripos($link, "http://www.".$domain) || stripos($link, "https://www.".$domain)){
            $rank=$count;
        }
    }
    if (!$rank) $rank=101;
    return $rank;
}

Estou tendo alguns erros na curl_setopt( $ch, CURLOPT_USERAGENT, $useragents[rand(0, sizeof($useragents)-1)] );
E com o while($bp=strpos($resp, "<h3 class=", $bp+1)) {