I understand the network issues that you are experiencing with the Slingbox. First, we need to know if you already tested the Slingbox in a different location using another router; this could be caused by a network restriction at your home. Testing the Slingbox in another location, will determine if there is a network issue or if the trouble is with the Slingbox and the power supply.
I recommend performing all the steps that you can find here:
Also, another step that you can try to perform is to reset the router at home and power cycle the Slingbox, it could work.