Error in posts per page/pages’ navigation

Dear:

I’m using WP 2.5.1.

I set in my settings how many posts to show in my static page (this page uses a template).
But when I click to the link to go to next (or the previous one) page, although I see a new url (e.g. myhost.com/post/page/2) I always see the same posts… I don’t think it’s a template mistake because I use it for my index.php and there it works… Here my template code: http://wordpress.pastebin.ca/1055549…