98367b2 created the issue

I've been successfully using Cyberduck to access my university's Desire2Learn learning management system using WebDAV. But today I cannot create folders. I can upload files just fine. But if I drag a folder to Cyberduck, or if I use Cyberduck's "New Folder" command, I get an "I/O Error" saying that it cannot create the folder because it's an "unsupported media type."