Missleading error message: "Could not read MBR"

After activating the image backup for a client and starting a full image backup through the web interface, I get the following error message in the client protocol:

Could not read MBR
Cannot retrieve master boot record (MBR) for the disk from the client.

After digging around a bit I noticed that the volume to image was not specified.
After entering volume C, the image backup started as expected.

I would suggest to adjust the error message for this case.

Server: UrBackup 2.4.11
Client: UrBackup 2.4.11