As many of you may have noticed, the Office Live reports have not been working properly for the last couple months (actually since the very start of Office Live!), data has been inaccurate and slow to update. The best thing you can do is contact support and let them know of the issue. The more people contact support the better, this will them know that there definitely is a problem. The next thing to do is switch over to using Google Analytics, Google Analytics is far superior to the Office Live reports: http://solutionsforofficelive.com/googleanalytics.aspx.
UPDATE: Some of the reports appear to be functioning correctly now. Though data still may not be completely accurate.