I understand that you are having some issues with the SlingPlayer for Android Tablets application since you are not able to get the connection to your Slingbox PRO-HD.
The fact that you are able to get the connection to your Slingbox PRO-HD when running the SlingPlayer for Android devices indicates that the Slingbox PRO-HD is working fine, otherwise, you will not be able to get the remote connection to your Slingbox running the Mobile application.
With this in mind, I encourage you to test the connection on your tablet from a different network, since this issue might be related to any kind of restriction on your current network. Make sure to follow this recommendation and let us know how it works for you.
It appears to be only an issue on my inlaws WiFi. Any suggestion on settings changes that would allow the tablet version to work on thier WiFi, or is it an issue with thier ISP? They have Charter. Unfortunatly, I can not try anything out now since they live 300 miles away, but I will be back there around Christmas.