I would like to welcome you to the answers forums. You post is missing a little information but I am going to take what I can from it. I see that you have a D-link DSL 2730B. I am not sure how that unit is effecting the setup of the video. When you said the Video appears and than blocks, do you mean that the video come in and than gets choppy and blocky or does it just freeze up? Also what Slingbox are you trying to configure?
If the issue you are having is with the router you might want to look at these articles.
Hope these help,
Sling Moderation Team