Thanks for taking the time to post to the forums! I see you're having trouble with your Slingbox PRO-HD. It looks to me like your Slingbox is not set up for Internet viewing. Which means you may need to port forward your router. We normally see this as the issue when you can't connect to Slingplayer Apps only.
Here is an article that will help you discover whether or not you are set up for internet viewing:
If your Slingbox does need to be set up for Internet viewing and you need some help you can check out portforward.com. There you will be able to select your routers manufacturer and model number along with the Slingbox as the application and it will walk you step by step through how to port forward your router.
Hopefully This Resolves Your Issue
The Sling Media Moderation Team