Hackintosh Fix How-To: Time Machine could not be configured. The built-in network interface could not be found
Run terminal (hit the apple key and space bar at the same time then type Terminal and select it from the list)
Then type the following:
sudo mv /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist /Library/Preferences/SystemConfiguration/NetworkInterfaces.plist.old
Then hit enter and if it asks for your password enter it.
Then reboot and voila!