How to Fix iTunes Error 1004 on iPhone 4 restoration !! [Guide]

More complete solution for those not knowing where to find the file:


On Mac:

  Open Finder
  Hold down COMMAND + SHIFT keys and press 'G'
  Enter "/private/etc/" in the field and press "Go"
  Find "hosts" file in the directory
  Drag the file to your desktop
  Open it in text editor
  Remove the line that has gs.apple.com entirely or put a # at the beginning of it to comment it out
  Save the file
  Drag it back to the /private/etc/ folder.
  You'd need to enter your username and password to authenticate the move
On Windows:

Locate the hosts file in one of the following directories:
Windows 95/98/Me c:\windows\hosts
Windows NT/2000/XP Pro c:\winnt\system32\drivers\etc\hosts
Windows XP, Vista, 7 c:\windows\system32\drivers\etc\hosts
Right click and click on "Open With..." and then click on "Notepad" on the list.
Remove the line that has gs.apple.com completely and save the file.
This should work fine.