Chance are, you redirected gs.apple.com to 220.127.116.11 to make sure you can restore to an earlier version of the iPhone software for 3G/3GS.
It seems iTunes 9.2 authenticates the restore at two different points in time. Once right after it extracts the restore data, and the second time after it verifies the restore was completed.
I noticed that I got a 3004 error after I disabled my internet after the verification process started, which made me realize the cause.. It's interesting that the error message was 3004 instead of 1004 though.
On MacOS X, edit your /etc/hosts file to remove the line that says:
(Open the Terminal application in your /Application/Utilities/ folder. Then enter the following command:
Enter your password when prompted. Find the gs.apple.com line and remove it for the time being.)
On Windows, I think your hosts file may be in:
I wouldn't know though....