Backup Drive has changed to A: to B:

If you back up to a floppy disk in A: drive or B: drive, then the "Drive to Backup To" should be A: or B:, and you need to ensure you have a formatted floppy disk in the drive.

If you back up your data to a memory stick, pen drive, or external hard drive, then the drive letter will usually NOT be A:, B:, or C:, and you would need to ensure "Other Drive" is selected and the appropriate drive letter entered. In the example below, the memory stick is drive F:

If you do have A: or B: selected by mistake and you intended to back up to another drive, you may receive one of the following messages:
"Error Reading Drive A:"
"Error Reading Drive B:"
"Please Check there is a formatted disk in floppy drive A:"
"Please Check there is a formatted disk in floppy drive B:"

Just select "Other Drive" and enter the drive letter you are backing up to.

A full step by step backup guide can be found here.