[問題]版面管理 Not Found

[marty1101]

遇到一個粉奇怪的現象, 就是在控制台裡的版面管理區, 有時候一切正常, 有時後卻會出現:

Not Found
The requested URL /forum/admin/admin_s.php was not found on this server.

Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.
--------------------------------------------------------------------------------
Apache/1.3.29 Server at http://www.sinew.net Port 80

上面這個訊息是按管理選項出現的, 其餘兩個分別是:
權限設定: 找不到 /forum/admin/admin_auth.php
快速刪文: 找不到/forum/admin/admin__prune.php

新裝的phpbb 2.0.6，沒加給個ＭＯＤ ....

追了粉久就迷路了, 有人碰過這個情況嗎?

謝!