I do apologize that you are experiencing issues with streaming from your Slingbox 500. The blue screen you are seeing is a result of HDCP from your cable provider. If your set top box only has an HDMI out, you will need an HDMI to component adapter that works with HDCP. For more information, check out the links below. Hope this helps!
- Slingbox.com - Using an HDMI video source with the Slingbox 500
- Slingbox.com - I get no video with any SlingPlayer (Watch, Windows, or Mac OS)
Sling Media Moderation Team