First of all my problem is: I got my homepage instead a 404 (or post not found) if I try to reach a nonexistent page, the "post not found" works only if I reach a url like "http://mydomain.com/2005/10/14/something" with url like "http://mydomain.com/2005/something" or "http://mydomain.com/something" I always reach the homepage
Then I have another problem, if I try to reach the wp-newblog.php from a user blog, I got the signup page in the user blog template! This is not acceptable at all.
This is my .htaccess: http://www.rafb.net/paste/results/HZp1hB61.html
Could you give me some hints please? Thank you.