When the user inserts a DVD into the drive, it asks for a username and password. If the user (normal non-admin) enters their username and password, it rejects that. If I enter the admin username and password, it works fine and OSX will mount the DVD but later won't work again after it forgets those cached credentials.
I've tried adjusting the permissions on the "volumes" folder, but I'm a little afraid to do too much on that because the user has mounted network shares too. Wouldn't want the wrong permissions to propagate down.
The affected version is 10.7.5