I can try transferring the file I have here to my home system (via ssh, of course, to avoid more possible problems) and running the upgrade again to see if that makes a difference...

Copying the "known good" file to your home computer is a good idea, but you don't need to run the upgrade to find out if it was a corrupted file. Just do a binary file compare of the file from work and the file from home. They should be identical. If they are, then it wasn't a corrupted upgrade file that was the problem.