You almost hit it. It's a port assignment fix for local viewing plus a port redirection (port forwarding) fix for remote internet viewing.
SlingPlayer needs two pieces of info to establish a connection and watch:
- Where is the Slingbox. (IP address)
- What port should be used.
Sounds like you've got the address part working so I'll skip that. I will say that for multiple Slings on the same LAN, it is a very good idea to give them static IPs instead of using DHCP. This isn't an absolute requirement, but it makes things much easier if you are also setting up remote viewing.
Slingbox needs its own port for the same reasons it needs its own IP. The default port for Slingbox is 5001. This can be changed when running the setup assistant. I'd suggest leaving one alone (5001) and assigning the other one to 5002. It doesn't matter which is which as long as they are not the same.
If you only need to watch over the LAN and your Player's Slingbox directory uses SlingID to find your boxes, you're all done. If the Directory uses manual entries (Direct Connect IP + Port), change the port to reflect Slingbox #2's new assignment.
For remote viewing, once you have reached this point all you need to do is go into your router and adjust port forwarding to send 5001 to Sling #1's IP, and 5002 to Sling #2's IP. They should be two separate entries in your router's port forwarding/firewall config.
Hope this helps !