An unknown error has occurred (3194)

Hi,

I have an issuse with my iPhone 3Gs. The firmware of my iPhone was 4.2.1 and I updated it to (iOS 4.3) easily, but when I try to update it to (iOS 4.3.1) this message appears : "The iPhone "Bassim" could not be updated. An unknown error has occurred (3194)".

Any help? 😟