Thanks for using Apple Support Communities. I recommend trying the steps pertinent to error 3004 from this article:
Errors 3000-3999 (3004, 3013, 3018, 3164, 3194, and so on): Error codes in the 3000 range generally mean that iTunes can't contact the update server (gs.apple.com) on ports 80 or 443.
- Update to the latest version of iTunes.
- Verify the computer's date and time are accurate.
- Check that your security or firewall software isn't interfering with ports 80 or 443 or with the server gs.apple.com.
- Follow these steps to troubleshoot security software. Often, uninstalling third-party security software will resolve these errors.
- An entry in your hosts file may be redirecting requests to gs.apple.com (go to "Unable to contact the iOS software update server gs.apple.com" above).
- Internet proxy settings can cause this issue. If you're using a proxy, try again without using a proxy.
- Test restoring while connected to a known-good network.
If you're using a Mac, this section may also help:
Error 3004: If you're using a Mac, you may be able to resolve an error 3004 by quitting iTunes and using the following command in the command line: dscacheutil -flushcache.