When ghost created the image did it create 1 file or more? You can tell it to span the images so they will fit on different media such as DVDs. For a complete ghost image you would need all of the files to be present.
Regarding the boot issues, I'm not familiar with ghostcast server but it could be possible you need to load NIC drivers in to the ghost boot disk. Creating a boot disk manually may be an option. Not sure how valid to your version these instructions are but it could be a similar process:
http://service1.symantec.com/SUPPORT/on-technology.nsf/docid/2000040710064725http://service1.symantec.com/SUPPORT/on-technology.nsf/docid/2000062113392125