Hi I have the exact same problem. I have read on another forum that if you update your apps via itunes (not directly on iphone) that the old version of the app goes into the recycle bin (if running Windows). But unfortunately for me I had already emptied my recyle bin before I found that out. Does anyone know of any other way to revert back to 2.1 or if you can restore the deleted items from the recycle bin?
It seems that you are having some issues with the SlingPlayer Mobile application for iPhone ever since you updated it to the latest version.
The following thread will provide you with some information that might help you to fix this issue.