It sounds like you are recieving a verison of copywrite portection. My advised is to elminate the HDMI and use component straight threw you will not recieve this issue anymore. So use component out of direct tv box to slingbox in and out of slingbox to tv with component. Here is some information to better help you understand whats going on.
When I connect my set-top box to my TV with HDMI connections, I can't stream video at all using any version of SlingPlayer. Why?
Thanks for posting
SlingMedia Technical Support