5.0 is Rock not ROME. Most recent ROME isos are here. Anyone wishing to install ROME is encouraged to try ROME Plasma6.
First did you check checksums for the .iso files? How did you burn to USB?
Those 2 quotes suggest a corrupted download, a bad copy to usb, or copy to usb done incorrectly. It may be helpful to read Rock Release Notes. Particularly the “Boot from USB section”.
If there is possibility of a corrupted download user may first just try downloading again or better try downloading from terminal.
I normally download .iso files like this:
$ aria2c -c -m 0 https://example.com/file.iso
And copy the .iso file to a flash drive using ROSA Image Writer. You may alternatively dd the image to your USB stick:
sudo dd if=<iso_name> of=<usb_drive> bs=4M conv=fdatasync status=progress
Replace <iso_name> with the path to the ISO and <usb_drive> with the device node of the USB drive, i.e. /dev/sdb.