iOS 5 upgrade error 1654

In short, I can't upgrade my iPad 1 (32Gb, WiFi), due to the fact I'm getting an error about not being able to restore, with code 1654.

In looking around, it appears to be some sort of USB issue. This is odd, though, as I'm using the same cable and port that I've used since I had the thing, and have done all previous updates through the same port/cable combination. I'm not sure why it would be a problem all of a sudden.

Anyone else run into this - how'd you get around it?