啟用sitemap外掛後，修改文章出現問題??

我啟用sitemap外掛後，修改文章更新後就出現下面這些錯誤??
我到tem/sitemap/1/也找不到sitemap1.gz的檔案??
請問一下，有沒有人知道是怎麼回事嗎??

lifetype1.2.5，智邦主機，1.2_sitemap外掛。

程式碼:

Sitemap Notification Received

Your Sitemap has been successfully added to our list of Sitemaps to crawl. If this is the first time you are notifying Google about this Sitemap, please add it via http://www.google.com/webmasters/tools/ so you can track its status. Please note that we do not add all submitted URLs to our index, and we cannot make any predictions or guarantees about when or if they will appear.
Exception message: Cannot modify header information - headers already sent by (output started at /raid/vhost/musa.url.tw/www/plugins/sitemap/pluginsitemap.class.php:205)
Error code: 2
-- Backtrace --
/raid/vhost/musa.url.tw/www/class/view/view.class.php(321): header
/raid/vhost/musa.url.tw/www/class/view/admin/adminview.class.php(112): view.render
/raid/vhost/musa.url.tw/www/class/view/admin/admintemplatedview.class.php(36): adminview.render
/raid/vhost/musa.url.tw/www/class/view/admin/adminpostslistview.class.php(205): admintemplatedview.render
/raid/vhost/musa.url.tw/www/class/controller/controller.class.php(379): adminpostslistview.render
/raid/vhost/musa.url.tw/www/admin.php(43): admincontroller.process

Exception message: Cannot modify header information - headers already sent by (output started at /raid/vhost/musa.url.tw/www/plugins/sitemap/pluginsitemap.class.php:205)
Error code: 2
-- Backtrace --