WP Blog “looses” Permalinks Config after some time

Hi all,

I have been suffering this problem since my update to WP 2.5 a long time ago. I thought it might solve itself after the subsequent upgrades but it hasn’t, and the problem is driving me crazy because I cannot find anything wrong in my configuration…

THE PROBLEM:

Some times, I try to access a post with my (used since I first installed the blog) “https://www.xxx.com/2009/03/06/sample-post/” permalink configuration, only to find a 404 error.

I found that going to WP options>Permalinks and saving the same config again (I don’t even have to change it) solves the problem for some time. But after a RANDOM period of time, it happens again!!! It’s mind boggling!

My .htaccess config is:
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress
php_value memory_limit 240M

and its permissions are set to 755

Does anyone know why this happens, and can give me a way to solve it?

Thanks in advance!