During a Linux installation you can run into this error message: "invalid magic number you have to load the kernel first".
This means that your Live USB creation went wrong or your USB thumb drive is unreliable.
*Try another thumb drive and see if the install boots correctly.*
If a new thumb drive fails it could be the program / application you are using to make the .iso bootable.
I can't stress enough that it is very important to verify the integrity of the Linux .iso that you download.
To verify the Linux .iso look for the md5sum or the sha256sum that is on the page of the Linux distro that you downloaded.
In some cases on some websites for Linux .iso downloads you will have to download a text file that will give you all of the md5sum's or sha256sum's.
For more help with thumb drives see my Blog post:
"How To Make A USB Thumb Drive Bootable With Linux"