Missing parameter in configuration file. Keyword: path

After the error message, try hitting Tab, type in live and hit Enter. This should get you to the Ubuntu desktop from where you can use the Install icon to go forward with the installation.

This is a bug. It happens when you create a bootable USB stick with an older version of Ubuntu than the version being installed on the USB stick.

Although the answer selected by the person who asked the question works to get around the issue it does not fix it as you have to do it every time you boot the USB stick.

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To fix the USB installation so you do not have to type live and hit Enter every time you want to use it to live boot:

In the boot: prompt after you hit the error above, type live and press Enter, to start the Live USB session.

Open a terminal (e.g. with Ctrl+Alt+t) and type each command line below one by one:

sudo -i
apt-get update
apt-get install syslinux
mount | grep cdrom

The last command above tells you to which device your bootable USB is on.

Important! replace <device> in the command below in the terminal with the device in the output of the last command above. Which will be something like /dev/sdb1

syslinux <device>

For a more detailed version of this answer see this answer.