Does MCEBuddy have access to \\DISKSTATION\Media\Movies? Have you entered the credentials for the network drive into MCEBuddy? If not then MCEBuddy can’t access it. Unless you’re running MCEBuddy as a command line engine (which runs in the context of the logged in user), it runs in kernel space and user space mappings dont’ exist there.
See the Common Issues post for details on this error and how to fix it.