So it can't setup the loop device?The first one looks like an fs error, though.Do you get the same error with both USB sticks you tried? Did you prepare them in the same way? Are they the same type of stick?
Maybe you should swap notes (or systems) with the OP in https://bbs.archlinux.org/viewtopic.php?id=146937 .What DE/WM are you using?Are the mount points there on boot? Are the file systems mounted on boot?