php curl登录论坛,但不会保持登录?

我正试图从一个私人论坛中提取一些数据。我创建了一个使用curl登录的PHP脚本,以及使用domdocument提取页面数据。

我已经使用脚本成功登录,但它的作用就像我尝试使用loadhtmlfile()加载网页时从未登录过一样。

有人告诉我可能需要发送cookie头?但我不知道该怎么做,甚至不知道是否有必要。

有人有什么想法吗?

    <?
function vBulletinLogin($user, $pass)
{
       $md5Pass = md5($pass);
       $data = "do=login&url=index.php&vb_login_md5password=$md5Pass&vb_login_username=$user&cookieuser=1";
       $ch = curl_init();

        curl_setopt ($ch, CURLOPT_URL, "****"); // replace ** with tt
        curl_setopt ($ch, CURLOPT_USERAGENT, "Mozilla/4.0 (compatible; MSIE 5.01; Windows NT 5.0)");
        curl_setopt ($ch, CURLOPT_TIMEOUT, '10');
        curl_setopt($ch, CURLOPT_POST, 1);
        curl_setopt($ch,CURLOPT_POSTFIELDS,$data);
        curl_setopt($ch, CURLOPT_COOKIEJAR, "/public_html/phpcrawl/cookies.txt");
        curl_setopt($ch, CURLOPT_COOKIEFILE, "/public_html/phpcrawl/cookies.txt");
        curl_setopt($ch, CURLOPT_FOLLOWLOCATION, 1);
        curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_REFERRER, "****"); 
        $store = curl_exec ($ch);
        echo $store; <- **this shows that I have successully logged in, it gives me a welcome message**
        print_r($_COOKIE);

        curl_close($ch);

       $pos = strpos($store, "Thank you for logging in");
       if($pos === FALSE) RETURN 0;
       else RETURN 1;

}
if(vBulletinLogin("****","****")) echo "Logged In";
else echo "Failed to Login check User / Pass";

$url="http://texturl.com";
echo $url."<br>";

//get new HTML document
$html = new DOMDocument(); 

$html->loadHTMLFile($url);
print $html->saveHTML(); <- shows a login and password box saying I am not logged in.