WordPress MU

My entire site went down after changing to a new theme.
http://paradiseparkmasonicclub.com/blogs/
So I upgraded to 2.7 and was able to log in and get at least the main site back up and running. I believe this is because it is using the database information from the blog. Not sure what I did wrong in setup.

All of my other blogs are gone, and I can't get in to them to even edit them. Even if I create a new blog
http://paradiseparkmasonicclub.com/blogs/manager/
http://paradiseparkmasonicclub.com/blogs/president/
http://paradiseparkmasonicclub.com/blogs/boardvp/

Anyone have any ideas?

Disable all plugins and all themes except default one.
Try to access blogs.
Then enable plugins/themes one-by-one.

Is the .htaccess file there?

Do you still have the site admin menu in the backend?

Sorry, what is the default for Word Press MU theme.

Is it Word Press MU default or..

Word Press Classic?

Andrea, yes I do have access to the admin page.

Andrea,

To answer your other question. The backend for my admin site is up. But it doesn't work for any of my other blogs in my site. I disabled all my themes and plugins. Except Word Press MU Default.

Another interesting fact, I cannot create a new blog. Ok, so let me be more specific. I can create the blog, but it doesn't show up either.

How far back did you upgrade from?
Compare the wp-config=sample.php file to the one you have.
Ask your host is they made any changes on the server.
make sure .htaccess file is there (htaccess.dist is NOT the one that it reads to create permalinks).

I'm guessing it's an htaccess issue or something changed on the server becasue your main blog permalinks don't work either.