Just though I would try and save our users the headache of using this tool and not knowing it won't work in these situations. I don't use it but I know some have mentioned interest in it.
"Due to changes in syslinux, it is not currently possible to use usb-creator from 14.04 and earlier releases to write USB images for 15.04 or later; we believe that it is also not possible to use usb-creator from a 15.04 or later system to write USB images for earlier releases. For now the workaround is to use a matching release of Ubuntu to write the images, but we intend to issue updates soon to work around this incompatibility. 1325801, 1446646and 1499746"
Edited by pcpunk, 05 December 2015 - 01:43 AM.