WordPress MU

Hello, i just installed wpmu, it works well but when i try to create a new blog, i get 2 errors:

1) Not found on http://blog.site.com/user
2) When i try to login using user:pass i get redirect to the same page, it goes in loop.

Any suggestion ?

Thanks

http://mu.wordpress.org/forums/topic.php?id=1314&replies=2