I see a bunch of stuff on using usb-creator to make a live usb for ubuntu which is great.
What I don't see is what type of partition table and file system is required on the USB itself. Does it have to be fat32?
Please provide partition table ID, and file system type as well as commands:
sudo fdisk /dev/sdb # Make bootable and chose ID = c (W95 fat32 (lba) ) sudo mkfs.vfat -n 'ubuntu' /dev/sdb1