It seems that you are having some issues with your Slingbox PRO and the HDMI cable connection.
The main issue is that the Slingbox (any model) is not compatible with the HDMI cable, due to the copy-protection built in to their hardware. The following link will provide you with further information about this situation.
It seems that you are having some issues with your Slingbox since it shows the "HDTV does not support HDCP" error message.
This error message is not related to your Slingbox but your set top box (cable box, DVR or satellite receiver). It means that your cable service provider has applied an update that enabled the HDCP (High-bandwidth Digital Content Protection). I encourage you to check the following thread and check the included links:
Hope this helps!
Go Here and purchase this from AMAZON
IHave TW Cable and I use their SA Explorer 8300 HDC.After hooking this Splitter up it works. I have been using it now for 2 weeks and no problems at all. I have HDMI hookups with out any of the HDCP problems.This is a 2 port out splitter,1 HDMI line goes to the in port from the Cablebox,and on the out ports (2 ports)1 line goes to TV and the other line goes to the sling box.And don't forget to switch over to HDMI connection in your SlingBox settingsThis is pertaining to the SlingBox 500 For $18.00 its a great deal.....