请问：php输出div为何不显示

请教：php输出div为何不显示？

PHP code

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<?php if(!isset($_POST['username'])) {
    header("location: index.php");
}
if (!$_POST['name']) error("请输入名称"); 
if (!$_POST['name']) error("请输入姓名"); 
if (!$_POST['username']) error("请输入账号"); 
if (!$_POST['password']) error("请输入密码"); 
  $link = @mysql_connect($db_host, $db_user, $db_pwd)
  or die("无法连接资料库<br>" . mysql_errno() . " " . mysql_error());
  mysql_query("SET NAMES '$charset'");
  mysql_select_db($db_name, $link) or die("无法进入资料库$db_name");
  $sql = "SELECT * FROM uc_members where username='$_POST[username]'";
  if (mysql_num_rows(mysql_query($sql, $link)) != 0) error("此账号已经被注册");

  $sql = "INSERT INTO uc_members(bbsname,bbstype,name,username,password,email,regtime,regip,phone,idnumber,address,ps)
  VALUES('$_POST[bbsname]','$_POST[bbstype]','$_POST[name]','$_POST[username]','".md5($_POST['password'])."','$_POST[email]','".date("Y-m-d H:i:s",time()+$time_ctrl*3600)."','$_SERVER[REMOTE_ADDR]','$_POST[phone]','$_POST[idnumber]','$_POST[address]','')";
  $result = @mysql_query($sql, $link) or die("无法新增记录<br>" . mysql_errno() . " " . mysql_error());
  mysql_close($link);
  $html = file_get_contents("$html_dir/reg_ok.htm");
  echo preg_replace("/\\$([a-z0-9\_]+)/sie","$\\1", $html);
$username=$_POST['username'];
$password=$_POST['password'];
$name=$_POST['name'];
$phone=$_POST['phone'];
$idnumber=$_POST['idnumber'];
$address=$_POST['address'];
$email=$_POST['email'];
$copy = $_POST['username'];
$countFile = 0;
$countDir = 0; 
function copyDir($dirFrom,$dirTo){   
    global $countFile;   
    global $countDir;   
    if(is_file($dirTo)){ 
        die("创建失败！");   
    }elseif(is_dir($dirTo)){
        die(" 此 $dirTo 账号已有人申请：请回到<a href="javascript:history.back();">上一页</a>重新输入用户名！");   
    }elseif(!is_dir($dirFrom)){ 
        die(" $dirFrom 不存在！");
    }else{ 
        if(!mkdir($dirTo)){   
            die("发生未知错误，$dirTo 建立失败！有可能权限不足！");   
        }   
        $countDir++;   
    }   
    $handle = opendir($dirFrom);   
    while(($file_name = readdir($handle))!==false ){   
        $file_path_from = $dirFrom.DIRECTORY_SEPARATOR.$file_name;   
        $file_path_to = $dirTo.DIRECTORY_SEPARATOR.$file_name;   
        if($file_name!="." && $file_name!=".."){
            if(is_dir($file_path_from)){
                copyDir($file_path_from,$file_path_to);  
            }else{
                if(!copy($file_path_from,$file_path_to)){   
                    die("$file_path_from的时候发生未知错误，有可能权限不足！");   
                }   
                $countFile++;
            }   
        }   
    }   
    closedir($handle);
}   
copyDir("client","$copy");

echo "<div class='\"main_center' minwidth>
    <div class='\"main_middle\"'>
        <div class='\"main_checking\"'>
            <div class='\"main_checking01\"'>
                <div class='\"main_checking01fl\"'></div>
                <div class='\"main_checking01f\"'>
                    <div class='\"main_checking01fr_title\"'>创建成功：建立 $countFile 个文件！</div>
                </div>
            </div>
        </div>
    </div>
</div>";
?>

为什么这段不能显示呢？

PHP code

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echo "<div class='\"main_center' minwidth>
    <div class='\"main_middle\"'>
        <div class='\"main_checking\"'>
            <div class='\"main_checking01\"'>
                <div class='\"main_checking01fl\"'></div>
                <div class='\"main_checking01f\"'>
                    <div class='\"main_checking01fr_title\"'>创建成功：建立 $countFile 个文件！</div>
                </div>
            </div>
        </div>
    </div>
</div>";
 <div class="clear">
                 
              
              
        
            </div>