请问：php输出div为何不显示

请教：php输出div为何不显示？

PHP code

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--><?phpif (!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

<!--Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->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>