This error occurs when the device unexpectedly loses its USB connection with iTunes. This can occur if the device is manually disconnected during the restore process. This issue can be resolved by performing USB troubleshooting, using a different USB dock-connector cable, trying another USB port, restoring on another computer, or by eliminating conflicts from third-party security software.
Not knowing exacly what you tried.
Sayinfg everythng does not say WHAt you tried
If still problem, make an appointment at the Genius Bar of an Apple store .