Snap Deploy - Image Creating - USB "Local"

Hello,
I'm trying to use snap deploy to install an image on a new pc. I've created a boot CD w/ the bootable media creator which works fine. I have the image on an external USB drive, however when i boot to the CD with the drive connected the software (snap deploy) is seeing the Drive (D) (Dell Portable Hard Drive) however when i try to expand to get the mater image, it states: This is a local disk of the current machine. If the master image resides on the local disk, deployment to this machine will be unavailable..... Help....