I got errors too, my phone is the iPhone 4S jailbroken with Absinthe 2.0. What I did was hooked my iPhone up and allowed iTunes to restore and upgrade. It took some time but it worked perfectly.Actually not even getting an error code. And Hook, trust me, I've got no need to jailbreak again. I'm trying to remove jailbreak to install iOS 6. Looking around, looks like it might be a matter of installing in DFU mode. I've downloaded the file, just waiting to my iPad to finish to try it.
Good catch.. probably the first thing to do before doing the restore/update on the phone.did you update you itunes?