Thank you for posting in the forums! I'm sorry to hear you are unable to access the my mediafeature via SlingPlayer for Android Tablets. The reason is because there has not been an update to allow this feature to work with tablets.
As of right now my media will only work with SlingPlayer for iPhone and SlingPlayer for Android Phones.
Below is a link to an article from support.slingbox.com that explains this:
Hope this helps!
The Sling Moderation Team