I think PratheepArunRaj is right here - Customer Care is going to be the most effective method to get this resolved, as it appears to be specific to your login. They'll be able to log in to your account to troubleshoot and resolve the issue.
You are correct about not having to select a RS, I was just asking to see if you had tried it multiple ways and still getting the same error. I am working on asking some colleagues if they have seen this before and if so what was the cause / fix.
When you say you are an admin, if you go into Admin/User Management under the Access section do you have access to all options and also have the radio button checked?
If you don't want to put it on a public forum, feel free to email me the company you work for and I will see if I can see anything that looks out of the ordinary without getting deep like client care will be able to.
I didn't' ask this and should have but have any other data feeds been set up?
In your screenshot it doesn't show that you have a RS selected. The feeds will be unique to each RS. This is one of those questions like when people have computer problems and they are asked if they have it plugged in so I apologize, but did you select a RS prior to trying to add a feed?
It's not a crazy question Brandon, and while the screen cap shows no RS, I did try it both ways. And I tried all three RSs that I have access to here. Nothing.
Also, from the instructions I thought that you didn't need to select an RS to just Add a data feed because selecting the RS was in the creation dialog, but I could be wrong about that. Do you know for certain? I mean I would check it but… 😉