iTunes aborts iPad update with error 1631

I've just connect my iPad 32GB+3G to my Mac and opened iTunes 10. When I clicked on "Check for Updates", I got the following error message."iTunes could not check for an update to the carrier settings for your iPad. An unknown error occurred (1631).Make sure your network settings are correct and your network connection is active, or try again".Then I just toggle the Cellular Data switch from OFF