Been there!
Error 3194 has to do with TinyUmbrella blocking access to Apple's servers. You have to go to your hosts file, and delete 74.208.105.171 gs.apple.com.
On my computer (Windows 7), the hosts file is C:\Windows\System32\drivers\etc\hosts
Open it in notepad, remove the line, and save it in the same format as the hosts file. Don't save it as a text file.
Error 21 is the same thing. You get an error 21 when it can't update the firmware. It can't update the firmware if it can't verify the update with Apple.. but after you fix the hosts file, you should be good to go.