You may want to look into using another set of cables to connect the Slingbox to your video source. With HDMI connections, you could run into HDCP or SOC. Take a look at the links below for a more detailed explanation:
- Slingbox.com - I get no video with any SlingPlayer (Watch, Windows, or Mac OS)
- Slingbox.com - Using an HDMI video source with the Slingbox 500
Hope this helps!