Permalinks freehostia.com how to set?

my wordpress blog is hostet by freehostia.com
i’ve set up all well and it works great, but when i change it in permarlink mode and i click on a post it does not redirect me to that post, but to a 404 error page…

this is my .htaccess file:

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

# END WordPress

it seems that it doesn’t know where the posts are and how to reach them.

i need help.
thanks a lot