Our widgets make great use of an API that Amazon provides. Most of you may not be aware of this, but Amazon now requires all applications that use their Product Advertising API to make signed requests (for authentication purposes). As of August 15, 2009, all API calls that are not signed will be rejected.
I just (painfully) updated the widgets to comply with the new requirements. Hopefully this will be hiccup-free, but please contact us if you run into any trouble with your widgets. Thanks!