HTTP500-内部服务器异常

HTTP 500 - 内部服务器错误 求助
HTTP 500 - 内部服务器错误

服务器：IIS6+PHP5.2.5+MYSQL

以前装DEDE什么的PHP程序都很好，今天安装一个新程序，也安装成功了，网站大部分都正常，只有一个页面出现“HTTP 500 - 内部服务器错误”

也GOOGLE了也百度了，也根据网上提供的解决办法尝试一天了，都半夜了还没有解决，来求助了。

IWAM_MAME三处密码也设置了。

我现在感觉就是脑袋有点大。

下边是出错文件的代码，是不是文件本身出问题了，大伙帮忙给看看，谢谢拉。

require_once "global.php";

if($user_id == -1) sysmsg($lang_sysmsg['nologin'],'index.php');

$tpl->set('site_title',$nav["pm"].'-');

if($op == 'listpm') {

$str = "select t1.nickname,t2.* from friends_user as t1,friends_user_pm as t2 where pto='$username' and t1.username=t2.pfrom and box='1'";
$coObj = $data->getList($str,20);
$coObj->navchar = $lang_nav;
$tpl->set("navbar",$coObj->navbar(10));
$tpl->set("list",$coObj->field);
$tpl->set("pagejump",$coObj->pagejump());
$tpl->set("pm_content","pm_list.html");
$tpl->parse("pm.html");

} elseif($op =='viewpm') {

$vip <= 0 && sysmsg($lang['vip_only'],'person.php?op=joinvip');

//$id=$_GET["id"];
$arr = $db->get_one("select * from friends_user_pm where pto='$username' and id='$id'");
$free = $arr["free"];
$flag = $arr["readed"];
/*
if($free == 0 && $flag == 0)
{
if(!upPoint($username,"ViewPm","收取留言"))
{
sysmsg($lang_sysmsg['nopoints'],'person.php?op=buypoint');
}
}
*/
$db->query("update friends_user_pm set readed='1' where pto='$username' and id='$id'");
$str = "select t1.nickname,t2.* from friends_user as t1,friends_user_pm as t2 where t1.username=t2.pfrom and t2.pto='$username' and t2.id='$id'";
$coObj = $data->getList($str,1);
$tpl->set("list",$coObj->field);
$tpl->set("pm_content","pm_view.html");
$tpl->parse("pm.html");

} elseif($op =='newpm') {

//$pmcount = $db->get_one("SELECT COUNT(*) AS t FROM `friends_user_pm` WHERE `pfrom`='$username'");

//if($vip <= 0 && $pmcount['t'] == 3) {
// sysmsg($lang['pm_limit_novip'],'person.php?op=joinvip');
//}

if(checksubmit($_POST["Submit"]))
{
//$from = $_POST["from"];
//$to = $_POST["to"];
//$title = $_POST["title"];
//$msg = $_POST["msg"];
$time = date("Y-m-d H:i:s");
$db->query("INSERT INTO `friends_user_pm` (`pfrom`,`pto`,`title`,`msg`,`ptime`) VALUES ('$from','$to','$title','$msg','$time')");
$uinf = $db->get_one("SELECT `email` FROM `friends_user` WHERE `username`='$to'");
email_newpm($to,$uinf['email']);
sysmsg($system_msg[2026],'person.php');
}
else
{
$tpl->set("from",$username);
$tpl->set("to",$_GET["to"]);
$tpl->set("pm_content","pm_post.html");
$tpl->parse("pm.html");
}
} elseif($op == 'delpm') {
//$id = $_GET["id"];
$db->query("delete from friends_user_pm where pto='$username' and id='$id'");
sysmsg($system_msg[2027],'pm.php?op=ListPm');
}
?>





------解决方案--------------------
1.IIS中错误发送打开；
2.IE中“工具”-》“internet选项”-》“高级”中把“显示友好http错误信息”前面的钩去掉。

这样就能看到具体报错信息了，在根据错误位置调试程序吧。
------解决方案--------------------
鉴于：网站大部分都正常，只有一个页面出现“HTTP 500 - 内部服务器错误”


建议：一个一个地方的echo, 也能找到问题啊。
------解决方案--------------------