These features were working in the past, I only noted them failing for the first time today. If I attempt to add media to a gallery page it stays greyed out (as though a blank overlay were covering it) and it just hangs. If I try to edit a gallery I get a 500 server error. I can, however call up a "multiedit" page by attempting to edit the media already on a page, and that seems to work. This behavior is consistent across multiple different sites on a multi-site Drupal 7 installation. I've tried going to one of the sites, disabling Media Gallery and then re-enabling it and that has no effect. The permissions on the files folder for uploading media are correct, and indeed have not been changed.
Does this behavior ring any bells? Could it be a server issue? It's a shared server on a Hostmonster account so my access is limited, but a perusal of what logs are available via cpanel turned up nothing linked to my IP address.