Ubuntu Server USB-bootable drive kernel panic

I've created a USB bootable drive to install Ubuntu server. I make it all the way to a menu similar to this:

Ubuntu server menu

Once I select any of the options, though, I get the exit-code/error:

end Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009

Is there something I'm missing or a step I've skipped? Also, if this has been answered somewhere else, please point me in the direction.

Thanks for any help or info!