What I understand from your post, is that you can't get any video with the current TV set.
In this case, the problem could be because of the HDMI, which unfortunately is not compatible with the Slingbox at this point and unfortunately we can't assure that will work for you.
Does this mean that connecting the HDMI port to any HDTV(not to the Slingbox) will prevent the component video connected to the Slingbox from working properly?
I have the same problem. I get perfect audio and video to the Slingbox until I plug in the HDMI to my HDTX, then the video to the slingbox is gone and only the audio works.