I have a Cablevision Scientific Atlanta 4250 HD box. Can anyone help me?
Check out this thread: https://community.sling.com/thread/3300?tstart=0
Come back if it doesn't help.
Also, when I try port forward it tells me to put the Slingbox IP address in but it will not let me put letters in, What do I do?
That is because IP addresses don't have letters in, they are of the format 192.168.001.253. What are you trying to use ?