Multisite installation not working after move to new hosting

Hello! I’ve just finished moving our school district’s multisite WordPress installation from our own web server to a hosting service. We have hundreds of blogs and gigs of files in blogs.dir. I successfully moved over all of the files and the database and we changed our DNS entry to point to the hosting service. The site and its individual blogs all load, but we’re only getting text – no images or other file attachments are working. I can log in to the site, but I can’t get the dashboard to load.

This leads me to believe that there’s an issue with the .htaccess file. I removed our custom entries and went back to the vanilla WordPress MU htaccess definitions (we’ve been running WP since 2009), but it’s still not redirecting correctly. I think the problem lies with the change in the web root directory. On our web server, it was in /var/www/html/, but in this host, it’s in /home/schooldistrict/public_html/. I’ve made the changes as necessary in our database, but it’s still not working properly. I suspect there’s something I’m missing in our wp-config.php file that describes the path, like PATH_CURRENT_SITE, but when I’ve changed that, it hasn’t helped.

Any ideas? Has anyone been through something like this before? Thanks in advance!