What I understand from your post is that you're having problems setting the Slingbox up, however, I would recommend to provide more information about the issue that you're having.
For example, information about any error message, network layout, lights status, etc. That way, you will be able to receive a proper response from the forum users.
I had the exact same issue. I bought from eBay. Ran the setup. The network light on the box was blinking, which meant that the system wasn't finding the IP address from the router. After a few minutes I did what I do to my computer, unplug unit, and both ends of the Ethernet cable. Wait 5 minutes, and plugged it all back in again. It worked after that. Sounds too simplified I know, but did the trick for me. Good luck.