I have the HDS-600RS and am having the same issue. I can connect fine using 'watch' on Slingbox.com but the Slingcatcher won't connect.
My Slingcatcher finds my network and also my Slingbox (which is in the UK and I am in the US) but it won't connect due to a 'network error'.
Will the support line be able to guide me through the potential fixes available?
Also, I haven't re-configured my UK router yet. This is connected to my brother's computer. Will he need to do this or can I try remotely? I can 'factory reset' the Slingbox remotely. Would this help?
What I'm getting from your post, is that you're having problems connecting from the SlingCatcher.
In this case, if you try to connect the SlingCatcher on a different network already, I would recommend to discard any streaming restriction at the specific network and even try to connect using the Slingbox network IP address instead the Slingbox ID.
Also, you can check the following links