The problem is that your existing WinPE boot image is lacking the correct drivers for the network chipsets on the new hardware you are trying to image. Getting the loopback address is a clear indicator that the network interface is not working.
These two links should get you going in the right direction:
http://www.symantec.com/business/support/index?page=content&id=TECH110134
https://www-secure.symantec.com/connect/articles/do-i-have-correct-driver-winpe