More info:
I'm now getting this message on a group of clients when I try to image a lab.
"cannot open source file for transfer; check that file exists and permissions are set correctly"
This is under Download Client Upgrade and the status in the log is WARNING. Further down under To Virtual Partition it fails with the message "Copy failed: file not found: source = "Program Files\Symantec\Ghost\ghost.exe", dest = "ghost\ghost.exe" "
Now, we still have some labs that are imaging correctly, but this lab worked fine before the update.