【求助】网站突然无法“新增” “修改”文章、会员，提示：Cannot modify header ……

一进如JOOMLA的后台，顶端就提示：
Warning: session_destroy() [function.session-destroy]: Trying to destroy uninitialized session in …具体路径我就省略了…\session.php on line 97
Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at ……\libraries\joomla\session\session.php:97) in ……\libraries\joomla\session\session.php on line 531
Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at ……\l