I am seeing that you are not able to view your Slingbox on your Mac after the plug in update. I will be happy to answer this question for you.
The best way to try to resolve the plug in issue that you're having would be to try it on another web browser and you can also try clearing your cache and cookies from your web browser. Sometimes when we send out a plug in update and the browser itself hasn't updated, then it can cause a compatibility issue between the browser and the plug in update. Please check out the article below for our supported browsers and operating systems:
Hope this helps!
The Sling Moderation Team