curlpost有关问题

curl post问题
$voteurl="http://www.qq.com/wenjuan.show.php?act=sub&id=7&ucode=".$aid;
$header= array(
'Accept' => 'text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8',
'CURLOPT_COOKIE' => 'PHPSESSID=a1nvcdhsucj6av9vclsa435si2',
'CURLOPT_REFERER' => 'http://www.qq.com/wenjuan.show.php?id=7&ucode='.$aid,
'Origin' => 'http://www.qq.com',
'Content-Type' => 'application/x-www-form-urlencoded',
'Connection' => 'keep-alive',
);

$post = array(
'selid%5B%5D' => $id,
'submit' => '+%CC%E1+%BD%BB+',
);

$response = ihttp_request($voteurl, $post, $header);

怎么老提示500错误
------解决方案--------------------
函数 ihttp_request 存在吗？