如何会有错呢，简单的json读取_PHP

怎么会有错呢，简单的json读取
<?
$pingluninfo = <<<EOT
{
    "title":"123",
    "url":"http://localhost/?p=9",
    "ttime":1401327899094,
    "sourceid":"9",
    "parentid":"0",
    "categoryid":"",
    "ownerid":"",
    "metadata":"",
    "comments":[
        {
            "cmtid":"358",
            "ctime":1401327899094,
            "content":"2013年8月1日18:36:29 O(∩_∩)O~",
            "replyid":"0",
            "user":{
                "userid":"1",
                "nickname":"admin",
                "usericon":"",
                "userurl":"",
                "usermetadata":{
                    "area": "北京市",
                    "gender": "1",
                    "kk": "",
                    "level": 1
                }
            },
            "ip":"127.0.0.1",
            "useragent":"Mozilla/5.0 (Windows NT 6.1; rv:22.0) Gecko/20100101 Firefox/22.0",
            "channeltype":"1",
            "from":"",
            "spcount":"",
            "opcount":"",
            "attachment":[
                {
                    "type":1,
                    "desc":"",
                    "url":"http://img.sohu.itc/xxxx"
                }
            ]
        }
    ]
}
EOT;

$pingluninfo = json_decode($pingluninfo, true);
if(!$pingluninfo) {
die('错误的数据格式');
}
?>
总是输出错误的数据格式
------解决思路----------------------


<?php 
$pingluninfo = <<<EOT
{
    "title":"123",
    "url":"http://localhost/?p=9",
    "ttime":1401327899094,
    "sourceid":"9",
    "parentid":"0",
    "categoryid":"",
    "ownerid":"",
    "metadata":"",
    "comments":[
        {
            "cmtid":"358",
            "ctime":1401327899094,
            "content":"2013年8月1日18:36:29 O(∩_∩)O~",
            "replyid":"0",
            "user":{
                "userid":"1",
                "nickname":"admin",
                "usericon":"",
                "userurl":"",
                "usermetadata":{
                    "area": "北京市",
                    "gender": "1",