If this is the error that you are referring to .....
This device is not eligible for the requested build: Also sometimes displayed as an "error 3194." If you receive this alert, update to the latest version of iTunes. Third-party security software or router security settings can also cause this issue. To resolve this, follow Troubleshooting security software issues.
Click on the Troubleshooting security software link in blue above. You could try temproarily disabling your firewall and antivirus software first and then try again.