CLOSE ALL INSTANCES of your current Per Diem gadget before upgrading.

Tips:
The instance of the gadget which notified you
of the upgrade should have closed when you clicked the upgrade link.
However, you may have to close remaining instances if you have any open.
To make sure you've closed all instances, hit "StartButton + Spacebar"
to bring all instances to the front. Make sure you page through
your docked gadgets on the sidebar to ensure none are docked in a "hidden"
page.