14.04 - winusb gives me the error "cannot move file to a subdirectory of itself". How do I debug and fix?

$ sudo winusb --install win7-pro-x64.iso /dev/sde1
Mounting...
mount: block device /media/Ubuntu-Data/ISOs/win7-pro-x64.iso is write-protected, mounting read-only
Copying...
mv: cannot move ‘/media/winusb_target_1415893348_22764/BOOT’ to a subdirectory of itself, ‘/media/winusb_target_1415893348_22764/boot/BOOT’
Error occured !
Syncing...
Cleaning...
Umounting and removing '/media/winusb_iso_1415893348_22764'...
Umounting and removing '/media/winusb_target_1415893348_22764'...

the above is what is going on with my flash drive.

I've formatted the drive as Fat16, per these instructions: http://encoded.eternicode.com/creating-a-uefi-bootable-win7-usb-stick-from-linux

Is there something wrong with winusb?

note: I have a legal key to use with this iso, my laptop that I'm installing this to just doesn't have a CD drive.

I'm using Ubuntu 14.04
My laptop has UEFI and also has Ubuntu 14.04
Windows would be going on to it's own SSD (my laptop has two)

UPDATE: also happens with a Fat32 partition