If Sally, some blog functions are still in the restore process. Adsense gaget is a widget, and Blogger's recent update problem is effecting some widgets. Here are a few things to check
1. First make absolutely sure your adsense account is still valid. I noticed that you also have other ad vendors on your site, so this is the first thing I'd check.
2. IF you are sure your account is in good status with Adsense, then you might log into your adsense control panel, find the html code for the type of ads you are displaying, and then copy it back over to the widget.
Those are the first two steps that normal rectify anything you can do on your end to resolve the issue. Having good code on your site, and having a good account with Adsense is pretty much doing what you can do until Blogger irons out it's issue with the recent rollback.