Error setting up gfxboot
Such error occurred to me when installing ubuntu on Intel® Desktop Board DH67BL. What appeared to be a problem was that I was using VGA monitor on DVI port (using adapter from DVI to VGA).
When Installing Ubuntu Server 18.04 it actually helped typing "help" and hitting enter. Then installation menu appeared. However for Ubuntu Server 16.04 this didn't helped. So I changed to monitor with DVI interface using just DVI cable and this problem gone. Eventually I could install 16.04 successfully.
Hope it helps for someone.