I found this site, hopefully this will help you. Click Here
Below is the solution from that site:
After creating a USB bootable version of Ubuntu from the Startup Disk Creator (or usb-creator-gtk) and attempting to boot, I was greeted by the error above. It might look a bit scary but it’s really easy to fix, just plug the USB flash drive into a computer (windows or linux, mac too probably but I haven’t tried that.)
Solution 1:
Open the the syslinux folder in the root of the flash drive.
Inside is a file called syslinux.cfg you’ll want to edit that.
Find the line “ui gfxboot bootlogo” and simply remove the “ui “.
Save and try booting again.
Below is how my syslinux.cfg file looks after editing:
# D-I config version 2.0
include menu.cfg
default vesamenu.c32
prompt 0
timeout 50
gfxboot bootlogo
Solution 2
Alternatively it looks as though there is another way of fixing this issue if there is no “ui” in the file, this is to do as followed (as pointed out in the comments below):
Type “help” and press enter
Hit Enter again
This should boot correctly and shouldn’t need to be done every time.
Source: http://alexsleat.co.uk
This is bug 1325801. The wrong version of syslinux gets used, the one from the running system instead of the one from the ISO. If you have a runnable 16.04 live system, you can use it to make another one with Startup Disk Creator, or just use mkusb on the 14.04 system, which will give you a safer way to use dd, which works too.
Best Answer
As Filip Sohajek mentioned, you need to hit Tab.
Then you will see a set of options (live, live install, etc). Select the one that you like typing its name and pressing Enter.