Blog-Template: problems after create a new site

Hi,

When I'm logged in in the network and I create a new site by using blog template, it is showed a link to the new site and to the admin area. The link to the new site is wrong, it goes to a not found page. Appears this message:

"Apologies, but the page you requested could not be found. Perhaps searching will help."

When I'm not logged in the network and I will create a new user + site I noted it also goes to a not found page. In addition, the congratulations page that is shown after the site is created is different from my site. I do not know from where this page comes from.

Thanks.