canadadr - 4:10 am on Mar 22, 2011 (gmt 0)
Seems they are aware of this bug and are working on fixing it, here's the official message on GA blog:
Users of the AdSense reports inside of Google Analytics may have noticed that there have been discrepancies between the AdSense reports in Google Analytics and AdSense since March 16th. We’re aware of the issue and a fix is being rolled out at this time. The cause of the issue is not related to the new version of Google Analytics.