I am not able to install porteus to a usb stick at the moment. I had the same problem previously but somehow managed to install it in the end but now I can't find a way around the problem and cannot remember what I did before. The usb stick (sdc1) is formatted to ext4 but I am getting a message saying it cannot install because of error code 3. Here is the debug log:
You don't explain how you attempted to install Porteus. I would recommend booting from the latest Porteus version using 'copy2ram' cheatcode. Then it is as simple as:
1) Format the install device
2) Mount the device
3) Copy contents on ISO onto the device
4) cd into the boot directory on the device (super important)
5) Run the Porteus_installer_for_linux script in the boot directory (make sure you change directory into the same folder that contains this installer)
How do i become super user?
Wear your underpants on the outside and put on a cape.
Unfortunately this is the same disk I used before and I had to reformat it temporarily so I don't have the previous install to boot in to. I'm basically doing the exact steps you outlined but from within my installed distro (funtoo). I have formatted the disk to ext4, mounted the iso, copied the iso contents to the disk, did cd in to the boot folder on the disk and sh Porteus-installer-for-Linux.com, all as root. I still get the error though. I've reformatted the disk a few times in case there was a problem there but it didn't change anything.