It seems that you are having some issues in order to locate your Slingbox AV on your network.
Most of the times, this issue is related to the security software running on your computer. With this in mind, I recommend you to check the following link and follow the recommendations:
I also recommend you to check the following link in order to know if your Operating System and web browser versions are supported:
Finally, I recommend you to connect the Slingbox directly into the router in order to determine if the bridge connection might be somehow causing this connectivity issue.