There is no media in the device. Write the following label information on the DVD or other media and then insert the media ...

There is no media in the device. 
Write the following label information on the DVD or other media and then insert the media in the device to continue.

Label: {0}

This information will be used by Windows Server Backup to identify this backup at the time of recovery. Make sure to record the label information along with the backup media so that it can be identified when needed.