jury rigged: I copied the folder with my good install from my Powerbook to my iMac. Upon running VectorWorks on the iMac, I was prompted for the license information. After entering the codes for my personal copy, everything seems to work without a flaw.
Good thing the Mac doesn't have a registry...
Just to dispell the notion that the drives on some of these machines might not read the cd correctly, I made an image of the cd with my Powerbook, installed perfectly from the image to my Powerbook, and the iMac still failed to install from that image.