Thank you for using the answers forums. Sorry to hear you are having issues using a powerline adapter. If the Slingbox gets a solid network light when plugged directly in to the router, the Slingbox is working properly. In order for powerline adapters to work with the Slingbox, they need to be on the same electrical circuit in order to get and maintain a good connection. They also need to be plugged directly in to the wall outlets, not a power strip as they will not get the connection.
Hope this helps,
The Sling Moderation Team