@jimp:
Could be why, especially if the new box doesn't have a serial port or has some issue initializing it. Try removing the line from the config that activates the serial port, restore the altered file, and see if the behavior improves It would be under the <system>tag somewhere, "<enableserial>". Remove the line if it's there and then restore.</enableserial></system>
I can't test this now because I reconfigured by hand and put the box into production. This is almost certainly the issue though as the new box had the serial port disabled in the BIOS.
You might want to consider a warning and option to disable in the restore script, just as you have with interface remapping.