Site went down after activating Theme – HELP!

I installed and activated the Network theme on my WP MS site.

Now the root site is down and I can’t access it at all, including the admin dashboard. My other subsites within subfolders are still working fine, such as http://www.ehangar.com/directories.

I went into cPanel and checked and repaired the database, but to no avail.

What can you suggest I do now to get it back up again?