Permalinks and Previews

This might be a new one…

I’ve changed the directory that WordPress is instaled and am using permalinks. There is an index and htaccess file in the blog directory and even though htaccess is set as 666, WordPress thinks it’s not writeable. OK, so I write it by hand and the re-write rules seem correct:

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

All works fine for me, however, when another admin tries to preview a post, he gets a 404 error. When I preview a post, it’s fine. How can this be?