Trouble creating USB install disk

[ronald long]

I'm Using Ubuntu 14.04. I've downloaded the 9.10.1-U4 iso, and verified it.
I have a 4 gig USB key. I've tried formatting it a variety of different formats (MS Dos, Fat 16, Fat32, ext4 using GParted.
I managed for format it once with what appeared to be the freeNAS data, but it wouldn't boot (grub error).
At the moment dd can't open the usb key (at dev/sdc), giving me a Permission denied error.
I obviously need a bit more detail than is in section 2.2.1 of the user's guide, and haven't been able to find that.

thanks

 

[ronald long]

appear to have solved this. When I formatted with ext4, it made root the owner, so I had to use sudo dd to format. appears to be booting on the machine I plan to use as the NAS....