Not able to deploy Wiindows 7 from .wim on flashdrive

Hi, We are going to be deploying Windows 7 on about 150 computers. I have gone through the process to create the answer file, customize Windows 7, sysprepped/generalized it (in audit mode), and captured the image using imagex. It created a .wim file, which I then copied onto a bootable flashdrive. It is the only file on the flashdrive. When I try to boot from the .wim on the flashdrive I get a...