WordPress MU

I had a wordpress mu site set up and running and now i get an error message that says this:
No WPMU site defined on this host. If you are the owner of this site, please check Debugging WPMU for further assistance.

I'm not sure what happened to make it stop working.
But I've looked thru forum and I don't see the answer to this problem. I backed up the database, should i just install a fresh mu 2.7 (i had the older version)
do you think that would bring it all back (my blog that is)

Any help will be appreciated, thanks!

Can someone help with this post? I am not sure what to do.

What did you change/update before it stopped working?

You may also try to run a repair on your database as one or more of the tables may be corrupted. Try this first, since you have a backup, but if your backup has the corrupted tables a fresh install will give you the same problem.

i didnt change anything, it was working and then i didnt update my blog for a while and when i went to it, it gave me that error message.

i am going to try the database repair now and report back on what happens. thanks!

i checked and ran a repair on the database and it said everything was OK. I just tried to pull up site:
http://www.socialeguide.com and it still has the same message. what should i try now?

The wp-config.php file has changed. Try to use the new one for 3.7 and fill everything out again. I'm guessing this is the cause. You may need to fill in "domain_current_site" ans socialeguide.com, path is "/" and blogid should be "1" but you'll see in your database.

narroyo623: did u try to delete the .htaccess file? try delete it then run the blog, the .htacess file will be recreated. Also check your server error log for error.