Unfortunately, you CAN NOT use Ubuntu 10.10 to create a usb flash drive startup disc for Ubuntu 10.04 lts! Known issue.
Jordan_U: cjae: Yes, it’s a known bug as there were incompatible changes to syslinux between 10.04 and 10.10.
The solution then is:
2. Burn the iso to a cd, using something like k3b, Nero for Linux, Brasero, or your favourite CD/DVD burner. Remember you are not just copying the iso image, you want to Burn the image. (Tools/Burn image in K3B)
3. Boot off the 10.04 live CD.
4. Use Startup Disk Creator (System/Administration/Startup Disk Creator) to create the USB Flash Drive Startup.
Neat Bug! NOT!