Ghost: Problem creating image

Help please: I use Ghost 8 all the time to create images, then restore to multiple computers here at our little elementary school.
We bought a Gateway with 500 GB hard drive, and I want to same an image of it before I send it out to a classroom. However, Ghost crashes whether I boot from external floppy, CD or flash drive. I get “abort 8027” message every time. I want to put image on a 150GB My Book hard drive. OBvioiusly I don’t want to squeeze 500 gigs into 150 gigs, I want to only copy essential files.
Anyone know what I’m doing wrong? Thanks.