When you misconfigured any of your DNS IP, Gateway or the NIC card, you will face issue as "Failed to retrieve the pre-configuration file".
IP address which you assigned for SafeSquid proxy if blocked because of firewall, you will face issue as "Bad archive mirror". This is typically an error with the server failing to connect to the Internet.
'Note: ' If you face any error while installing SafeSquid Appliance Builder (SAB-ISO), you will get debugging logs information by pressing ALT+F4. To return back to previous screen press ALT+F1.