@flat4vw I guess a couple of things.
Instead of realtek.pxe you probably want to use realtek.kpxe.
The *?pxe files are for bios based computers. They will not boot on a uefi system.
The file is physically located in the FOG server in the /tftpboot directory.
How do you make the computer load the file? Update dhcp option 67 on your dhcp server. Either by the windows dhcp manager or if linux in /etc directory.