Make sure your router at the Slingbox location has the port open for whatever port you have used (5001, 443...etc..)  As Floyed says it's best to use a friends or hotspot location to verify you are connected.  If the laptop is what you used to setup the slingbox in the first place then it will know the Finder ID.  But to make sure go into the slingplayer at home and click on Slingbox in the menu at the top and edit the slingbox directory.  You will see the finder ID.  Copy it down for later use if needed.