@craigtighe Can/Will you confirm the exact settings of dhcp option 66 and 67?

dhcp option 66 must be the IP address of the new FOG server
dhcp option 67 should be undionly.kpxe (or undionly.kkpxe) Make sure its spelled correctly. Using pxelinux.0 WILL generate a kernel sync error. That is known, fog moved away from syslinux quite a few years ago.

And as Junkhacker said, if you could snap a clear picture with a mobile and place it here we can see the context of the error too.