I noticed today that when creating a FreeBSD 10 instance that it takes a long time to create the instance and then fails to pre install the OS. checking the console it reports that it fails to boot from CD. I destroyed the instance and uploaded a ISO of the FreeBSD 10 AMD64 image and then installed manually. That worked fine.
You may want to check the ISO you have on site is being properly mounted or it's not corrupt in some way