Unknown error occurred (-1)

My sister has purchased a iPhone 3Gs and I have tried to restore the iPhone. I have put it into iTunes and restore it but once all the loading and installing as reached the end there is a message box that comes up saying 'The iPhone "iPhone" could not be restored. An unknown error occoured (-1).' I have typed the error into Google and nothing is coming up. Also when we could access the phone, which we cannot do now as it now only has theUSB to iTunes display, the WiFi and Bluetooth is unaccessable. You could not click on it let alone turn them on and off. Can anybody help me with both queries? Thanks!