How do you make Wiki work in Multisite Installation?

I am trying to enable Wiki on my primary site for multisite. I only want it to be available for the primary site but not the ones people sign up with through Pro Sites. I want them to be able to collectively add their niche information to the main and only Wiki on the primary domain. I have enabled it on the specific domain and super admin and added an entry but I keep getting a 404 error. Is there something else I should be doing?